diff --git a/core/res/res/color/letterbox_background.xml b/core/res/res/color/letterbox_background.xml
deleted file mode 100644
index 955948ad2b6aa..0000000000000
--- a/core/res/res/color/letterbox_background.xml
+++ /dev/null
@@ -1,19 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
-  ~ Copyright (C) 2022 The Android Open Source Project
-  ~
-  ~ Licensed under the Apache License, Version 2.0 (the "License");
-  ~ you may not use this file except in compliance with the License.
-  ~ You may obtain a copy of the License at
-  ~
-  ~      http://www.apache.org/licenses/LICENSE-2.0
-  ~
-  ~ Unless required by applicable law or agreed to in writing, software
-  ~ distributed under the License is distributed on an "AS IS" BASIS,
-  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  ~ See the License for the specific language governing permissions and
-  ~ limitations under the License.
-  -->
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:color="@color/system_neutral1_500" android:lStar="5" />
-</selector>
diff --git a/core/res/res/values/config.xml b/core/res/res/values/config.xml
index ef51217a0805d..3b36c7a6402bb 100644
--- a/core/res/res/values/config.xml
+++ b/core/res/res/values/config.xml
@@ -5593,13 +5593,13 @@
 
     <!-- Blur radius for the Option 3 in R.integer.config_letterboxBackgroundType. Values < 0 are
         ignored and 0 is used. -->
-    <dimen name="config_letterboxBackgroundWallpaperBlurRadius">31dp</dimen>
+    <dimen name="config_letterboxBackgroundWallpaperBlurRadius">24dp</dimen>
 
     <!-- Alpha of a black translucent scrim showed over wallpaper letterbox background when
         the Option 3 is selected for R.integer.config_letterboxBackgroundType.
         Values < 0 or >= 1 are ignored and 0.0 (transparent) is used instead. -->
     <item name="config_letterboxBackgroundWallaperDarkScrimAlpha" format="float" type="dimen">
-        0.5
+        0.68
     </item>
 
     <!-- Corners appearance of the letterbox background.
@@ -5624,7 +5624,7 @@
             but isn't supported on the device or both dark scrim alpha and blur radius aren't
             provided.
      -->
-    <color name="config_letterboxBackgroundColor">@color/letterbox_background</color>
+    <color name="config_letterboxBackgroundColor">@color/system_on_secondary_fixed</color>
 
     <!-- Horizontal position of a center of the letterboxed app window.
         0 corresponds to the left side of the screen and 1 to the right side. If given value < 0
diff --git a/services/core/java/com/android/server/wm/LetterboxConfiguration.java b/services/core/java/com/android/server/wm/LetterboxConfiguration.java
index fda22cab62769..7a201a77c966f 100644
--- a/services/core/java/com/android/server/wm/LetterboxConfiguration.java
+++ b/services/core/java/com/android/server/wm/LetterboxConfiguration.java
@@ -85,6 +85,13 @@ final class LetterboxConfiguration {
     // TODO(b/288142656): Enable user aspect ratio settings by default.
     private static final boolean DEFAULT_VALUE_ENABLE_USER_ASPECT_RATIO_SETTINGS = false;
 
+    // Whether the letterbox wallpaper style is enabled by default
+    private static final String KEY_ENABLE_LETTERBOX_BACKGROUND_WALLPAPER =
+            "enable_letterbox_background_wallpaper";
+
+    // TODO(b/290048978): Enable wallpaper as default letterbox background.
+    private static final boolean DEFAULT_VALUE_ENABLE_LETTERBOX_BACKGROUND_WALLPAPER = false;
+
     /**
      * Override of aspect ratio for fixed orientation letterboxing that is set via ADB with
      * set-fixed-orientation-letterbox-aspect-ratio or via {@link
@@ -101,9 +108,16 @@ final class LetterboxConfiguration {
 
     /** Enum for Letterbox background type. */
     @Retention(RetentionPolicy.SOURCE)
-    @IntDef({LETTERBOX_BACKGROUND_SOLID_COLOR, LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND,
-            LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING, LETTERBOX_BACKGROUND_WALLPAPER})
+    @IntDef({LETTERBOX_BACKGROUND_OVERRIDE_UNSET,
+            LETTERBOX_BACKGROUND_SOLID_COLOR,
+            LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND,
+            LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING,
+            LETTERBOX_BACKGROUND_WALLPAPER})
     @interface LetterboxBackgroundType {};
+
+    /** No letterbox background style set. Using the one defined by DeviceConfig. */
+    static final int LETTERBOX_BACKGROUND_OVERRIDE_UNSET = -1;
+
     /** Solid background using color specified in R.color.config_letterboxBackgroundColor. */
     static final int LETTERBOX_BACKGROUND_SOLID_COLOR = 0;
 
@@ -183,14 +197,14 @@ final class LetterboxConfiguration {
     @Nullable private Integer mLetterboxBackgroundColorResourceIdOverride;
 
     @LetterboxBackgroundType
-    private int mLetterboxBackgroundType;
+    private final int mLetterboxBackgroundType;
 
-    // Blur radius for LETTERBOX_BACKGROUND_WALLPAPER option in mLetterboxBackgroundType.
+    // Blur radius for LETTERBOX_BACKGROUND_WALLPAPER option from getLetterboxBackgroundType().
     // Values <= 0 are ignored and 0 is used instead.
-    private int mLetterboxBackgroundWallpaperBlurRadius;
+    private int mLetterboxBackgroundWallpaperBlurRadiusPx;
 
     // Alpha of a black scrim shown over wallpaper letterbox background when
-    // LETTERBOX_BACKGROUND_WALLPAPER option is selected for mLetterboxBackgroundType.
+    // LETTERBOX_BACKGROUND_WALLPAPER option is returned from getLetterboxBackgroundType().
     // Values < 0 or >= 1 are ignored and 0.0 (transparent) is used instead.
     private float mLetterboxBackgroundWallpaperDarkScrimAlpha;
 
@@ -252,6 +266,11 @@ final class LetterboxConfiguration {
     // Allows to enable user aspect ratio settings ignoring flags.
     private boolean mUserAppAspectRatioSettingsOverrideEnabled;
 
+    // The override for letterbox background type in case it's different from
+    // LETTERBOX_BACKGROUND_OVERRIDE_UNSET
+    @LetterboxBackgroundType
+    private int mLetterboxBackgroundTypeOverride = LETTERBOX_BACKGROUND_OVERRIDE_UNSET;
+
     // Whether we should use split screen aspect ratio for the activity when camera compat treatment
     // is enabled and activity is connected to the camera in fullscreen.
     private final boolean mIsCameraCompatSplitScreenAspectRatioEnabled;
@@ -294,10 +313,10 @@ final class LetterboxConfiguration {
 
         mFixedOrientationLetterboxAspectRatio = mContext.getResources().getFloat(
                 R.dimen.config_fixedOrientationLetterboxAspectRatio);
+        mLetterboxBackgroundType = readLetterboxBackgroundTypeFromConfig(mContext);
         mLetterboxActivityCornersRadius = mContext.getResources().getInteger(
                 R.integer.config_letterboxActivityCornersRadius);
-        mLetterboxBackgroundType = readLetterboxBackgroundTypeFromConfig(mContext);
-        mLetterboxBackgroundWallpaperBlurRadius = mContext.getResources().getDimensionPixelSize(
+        mLetterboxBackgroundWallpaperBlurRadiusPx = mContext.getResources().getDimensionPixelSize(
                 R.dimen.config_letterboxBackgroundWallpaperBlurRadius);
         mLetterboxBackgroundWallpaperDarkScrimAlpha = mContext.getResources().getFloat(
                 R.dimen.config_letterboxBackgroundWallaperDarkScrimAlpha);
@@ -359,6 +378,8 @@ final class LetterboxConfiguration {
                         DEFAULT_VALUE_ENABLE_USER_ASPECT_RATIO_SETTINGS,
                         mContext.getResources().getBoolean(
                                 R.bool.config_appCompatUserAppAspectRatioSettingsIsEnabled))
+                .addDeviceConfigEntry(KEY_ENABLE_LETTERBOX_BACKGROUND_WALLPAPER,
+                        DEFAULT_VALUE_ENABLE_LETTERBOX_BACKGROUND_WALLPAPER, /* enabled */ true)
                 .build();
     }
 
@@ -497,25 +518,39 @@ final class LetterboxConfiguration {
     }
 
     /**
-     * Gets {@link LetterboxBackgroundType} specified in {@link
-     * com.android.internal.R.integer.config_letterboxBackgroundType} or over via ADB command.
+     * Gets {@link LetterboxBackgroundType} specified via ADB command or the default one.
      */
     @LetterboxBackgroundType
     int getLetterboxBackgroundType() {
-        return mLetterboxBackgroundType;
+        return mLetterboxBackgroundTypeOverride != LETTERBOX_BACKGROUND_OVERRIDE_UNSET
+                ? mLetterboxBackgroundTypeOverride
+                : getDefaultLetterboxBackgroundType();
     }
 
-    /** Sets letterbox background type. */
-    void setLetterboxBackgroundType(@LetterboxBackgroundType int backgroundType) {
-        mLetterboxBackgroundType = backgroundType;
+    /** Overrides the letterbox background type. */
+    void setLetterboxBackgroundTypeOverride(@LetterboxBackgroundType int backgroundType) {
+        mLetterboxBackgroundTypeOverride = backgroundType;
     }
 
     /**
-     * Resets cletterbox background type to {@link
-     * com.android.internal.R.integer.config_letterboxBackgroundType}.
+     * Resets letterbox background type value depending on the
+     * {@link #KEY_ENABLE_LETTERBOX_BACKGROUND_WALLPAPER} built time and runtime flags.
+     *
+     * <p>If enabled, the letterbox background type value is set toZ
+     * {@link #LETTERBOX_BACKGROUND_WALLPAPER}. When disabled the letterbox background type value
+     * comes from {@link R.integer.config_letterboxBackgroundType}.
      */
     void resetLetterboxBackgroundType() {
-        mLetterboxBackgroundType = readLetterboxBackgroundTypeFromConfig(mContext);
+        mLetterboxBackgroundTypeOverride = LETTERBOX_BACKGROUND_OVERRIDE_UNSET;
+    }
+
+    // Returns KEY_ENABLE_LETTERBOX_BACKGROUND_WALLPAPER if the DeviceConfig flag is enabled
+    // or the value in com.android.internal.R.integer.config_letterboxBackgroundType if the flag
+    // is disabled.
+    @LetterboxBackgroundType
+    private int getDefaultLetterboxBackgroundType() {
+        return mDeviceConfig.getFlagValue(KEY_ENABLE_LETTERBOX_BACKGROUND_WALLPAPER)
+                ? LETTERBOX_BACKGROUND_WALLPAPER : mLetterboxBackgroundType;
     }
 
     /** Returns a string representing the given {@link LetterboxBackgroundType}. */
@@ -548,7 +583,7 @@ final class LetterboxConfiguration {
 
     /**
      * Overrides alpha of a black scrim shown over wallpaper for {@link
-     * #LETTERBOX_BACKGROUND_WALLPAPER} option in {@link mLetterboxBackgroundType}.
+     * #LETTERBOX_BACKGROUND_WALLPAPER} option returned from {@link getLetterboxBackgroundType()}.
      *
      * <p>If given value is < 0 or >= 1, both it and a value of {@link
      * com.android.internal.R.dimen.config_letterboxBackgroundWallaperDarkScrimAlpha} are ignored
@@ -575,33 +610,33 @@ final class LetterboxConfiguration {
     }
 
     /**
-     * Overrides blur radius for {@link #LETTERBOX_BACKGROUND_WALLPAPER} option in
-     * {@link mLetterboxBackgroundType}.
+     * Overrides blur radius for {@link #LETTERBOX_BACKGROUND_WALLPAPER} option from
+     * {@link getLetterboxBackgroundType()}.
      *
      * <p> If given value <= 0, both it and a value of {@link
      * com.android.internal.R.dimen.config_letterboxBackgroundWallpaperBlurRadius} are ignored
      * and 0 is used instead.
      */
-    void setLetterboxBackgroundWallpaperBlurRadius(int radius) {
-        mLetterboxBackgroundWallpaperBlurRadius = radius;
+    void setLetterboxBackgroundWallpaperBlurRadiusPx(int radius) {
+        mLetterboxBackgroundWallpaperBlurRadiusPx = radius;
     }
 
     /**
-     * Resets blur raidus for {@link #LETTERBOX_BACKGROUND_WALLPAPER} option in {@link
-     * mLetterboxBackgroundType} to {@link
+     * Resets blur raidus for {@link #LETTERBOX_BACKGROUND_WALLPAPER} option returned by {@link
+     * getLetterboxBackgroundType()} to {@link
      * com.android.internal.R.dimen.config_letterboxBackgroundWallpaperBlurRadius}.
      */
-    void resetLetterboxBackgroundWallpaperBlurRadius() {
-        mLetterboxBackgroundWallpaperBlurRadius = mContext.getResources().getDimensionPixelSize(
+    void resetLetterboxBackgroundWallpaperBlurRadiusPx() {
+        mLetterboxBackgroundWallpaperBlurRadiusPx = mContext.getResources().getDimensionPixelSize(
                 com.android.internal.R.dimen.config_letterboxBackgroundWallpaperBlurRadius);
     }
 
     /**
-     * Gets blur raidus for {@link #LETTERBOX_BACKGROUND_WALLPAPER} option in {@link
-     * mLetterboxBackgroundType}.
+     * Gets blur raidus for {@link #LETTERBOX_BACKGROUND_WALLPAPER} option returned by {@link
+     * getLetterboxBackgroundType()}.
      */
-    int getLetterboxBackgroundWallpaperBlurRadius() {
-        return mLetterboxBackgroundWallpaperBlurRadius;
+    int getLetterboxBackgroundWallpaperBlurRadiusPx() {
+        return mLetterboxBackgroundWallpaperBlurRadiusPx;
     }
 
     /*
diff --git a/services/core/java/com/android/server/wm/LetterboxUiController.java b/services/core/java/com/android/server/wm/LetterboxUiController.java
index a816838293961..39f75703d71f3 100644
--- a/services/core/java/com/android/server/wm/LetterboxUiController.java
+++ b/services/core/java/com/android/server/wm/LetterboxUiController.java
@@ -894,7 +894,7 @@ final class LetterboxUiController {
                         this::shouldLetterboxHaveRoundedCorners,
                         this::getLetterboxBackgroundColor,
                         this::hasWallpaperBackgroundForLetterbox,
-                        this::getLetterboxWallpaperBlurRadius,
+                        this::getLetterboxWallpaperBlurRadiusPx,
                         this::getLetterboxWallpaperDarkScrimAlpha,
                         this::handleHorizontalDoubleTap,
                         this::handleVerticalDoubleTap,
@@ -1315,7 +1315,7 @@ final class LetterboxUiController {
             case LETTERBOX_BACKGROUND_WALLPAPER:
                 if (hasWallpaperBackgroundForLetterbox()) {
                     // Color is used for translucent scrim that dims wallpaper.
-                    return Color.valueOf(Color.BLACK);
+                    return mLetterboxConfiguration.getLetterboxBackgroundColor();
                 }
                 Slog.w(TAG, "Wallpaper option is selected for letterbox background but "
                         + "blur is not supported by a device or not supported in the current "
@@ -1472,10 +1472,10 @@ final class LetterboxUiController {
                         // Don't use wallpaper as a background if letterboxed for display cutout.
                         && isLetterboxedNotForDisplayCutout(mainWindow)
                         // Check that dark scrim alpha or blur radius are provided
-                        && (getLetterboxWallpaperBlurRadius() > 0
+                        && (getLetterboxWallpaperBlurRadiusPx() > 0
                                 || getLetterboxWallpaperDarkScrimAlpha() > 0)
                         // Check that blur is supported by a device if blur radius is provided.
-                        && (getLetterboxWallpaperBlurRadius() <= 0
+                        && (getLetterboxWallpaperBlurRadiusPx() <= 0
                                 || isLetterboxWallpaperBlurSupported());
         if (mShowWallpaperForLetterboxBackground != wallpaperShouldBeShown) {
             mShowWallpaperForLetterboxBackground = wallpaperShouldBeShown;
@@ -1483,9 +1483,9 @@ final class LetterboxUiController {
         }
     }
 
-    private int getLetterboxWallpaperBlurRadius() {
-        int blurRadius = mLetterboxConfiguration.getLetterboxBackgroundWallpaperBlurRadius();
-        return blurRadius < 0 ? 0 : blurRadius;
+    private int getLetterboxWallpaperBlurRadiusPx() {
+        int blurRadius = mLetterboxConfiguration.getLetterboxBackgroundWallpaperBlurRadiusPx();
+        return Math.max(blurRadius, 0);
     }
 
     private float getLetterboxWallpaperDarkScrimAlpha() {
@@ -1535,7 +1535,7 @@ final class LetterboxUiController {
             pw.println(prefix + "  letterboxBackgroundWallpaperDarkScrimAlpha="
                     + getLetterboxWallpaperDarkScrimAlpha());
             pw.println(prefix + "  letterboxBackgroundWallpaperBlurRadius="
-                    + getLetterboxWallpaperBlurRadius());
+                    + getLetterboxWallpaperBlurRadiusPx());
         }
 
         pw.println(prefix + "  isHorizontalReachabilityEnabled="
diff --git a/services/core/java/com/android/server/wm/WindowManagerShellCommand.java b/services/core/java/com/android/server/wm/WindowManagerShellCommand.java
index 05e858de8973b..f4781f9bc9f0c 100644
--- a/services/core/java/com/android/server/wm/WindowManagerShellCommand.java
+++ b/services/core/java/com/android/server/wm/WindowManagerShellCommand.java
@@ -41,6 +41,7 @@ import android.os.UserHandle;
 import android.provider.Settings;
 import android.util.DisplayMetrics;
 import android.util.Pair;
+import android.util.TypedValue;
 import android.view.Display;
 import android.view.IWindow;
 import android.view.IWindowManager;
@@ -728,7 +729,7 @@ public class WindowManagerShellCommand extends ShellCommand {
             return -1;
         }
         synchronized (mInternal.mGlobalLock) {
-            mLetterboxConfiguration.setLetterboxBackgroundType(backgroundType);
+            mLetterboxConfiguration.setLetterboxBackgroundTypeOverride(backgroundType);
         }
         return 0;
     }
@@ -770,10 +771,10 @@ public class WindowManagerShellCommand extends ShellCommand {
 
     private int runSetLetterboxBackgroundWallpaperBlurRadius(PrintWriter pw)
             throws RemoteException {
-        final int radius;
+        final int radiusDp;
         try {
             String arg = getNextArgRequired();
-            radius = Integer.parseInt(arg);
+            radiusDp = Integer.parseInt(arg);
         } catch (NumberFormatException  e) {
             getErrPrintWriter().println("Error: blur radius format " + e);
             return -1;
@@ -783,7 +784,9 @@ public class WindowManagerShellCommand extends ShellCommand {
             return -1;
         }
         synchronized (mInternal.mGlobalLock) {
-            mLetterboxConfiguration.setLetterboxBackgroundWallpaperBlurRadius(radius);
+            final int radiusPx = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
+                    radiusDp, mInternal.mContext.getResources().getDisplayMetrics());
+            mLetterboxConfiguration.setLetterboxBackgroundWallpaperBlurRadiusPx(radiusPx);
         }
         return 0;
     }
@@ -1050,7 +1053,7 @@ public class WindowManagerShellCommand extends ShellCommand {
                         mLetterboxConfiguration.resetLetterboxBackgroundColor();
                         break;
                     case "wallpaperBlurRadius":
-                        mLetterboxConfiguration.resetLetterboxBackgroundWallpaperBlurRadius();
+                        mLetterboxConfiguration.resetLetterboxBackgroundWallpaperBlurRadiusPx();
                         break;
                     case "wallpaperDarkScrimAlpha":
                         mLetterboxConfiguration.resetLetterboxBackgroundWallpaperDarkScrimAlpha();
@@ -1188,7 +1191,7 @@ public class WindowManagerShellCommand extends ShellCommand {
             mLetterboxConfiguration.resetLetterboxActivityCornersRadius();
             mLetterboxConfiguration.resetLetterboxBackgroundType();
             mLetterboxConfiguration.resetLetterboxBackgroundColor();
-            mLetterboxConfiguration.resetLetterboxBackgroundWallpaperBlurRadius();
+            mLetterboxConfiguration.resetLetterboxBackgroundWallpaperBlurRadiusPx();
             mLetterboxConfiguration.resetLetterboxBackgroundWallpaperDarkScrimAlpha();
             mLetterboxConfiguration.resetLetterboxHorizontalPositionMultiplier();
             mLetterboxConfiguration.resetIsHorizontalReachabilityEnabled();
@@ -1262,7 +1265,7 @@ public class WindowManagerShellCommand extends ShellCommand {
             pw.println("    Background color: " + Integer.toHexString(
                     mLetterboxConfiguration.getLetterboxBackgroundColor().toArgb()));
             pw.println("    Wallpaper blur radius: "
-                    + mLetterboxConfiguration.getLetterboxBackgroundWallpaperBlurRadius());
+                    + mLetterboxConfiguration.getLetterboxBackgroundWallpaperBlurRadiusPx());
             pw.println("    Wallpaper dark scrim alpha: "
                     + mLetterboxConfiguration.getLetterboxBackgroundWallpaperDarkScrimAlpha());
             pw.println("Is letterboxing for translucent activities enabled: "
diff --git a/services/tests/wmtests/src/com/android/server/wm/WindowManagerServiceTests.java b/services/tests/wmtests/src/com/android/server/wm/WindowManagerServiceTests.java
index 5c1b262a9dc8a..45331f76fa4ce 100644
--- a/services/tests/wmtests/src/com/android/server/wm/WindowManagerServiceTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/WindowManagerServiceTests.java
@@ -1036,7 +1036,7 @@ public class WindowManagerServiceTests extends WindowTestsBase {
 
     private boolean setupLetterboxConfigurationWithBackgroundType(
             @LetterboxConfiguration.LetterboxBackgroundType int letterboxBackgroundType) {
-        mWm.mLetterboxConfiguration.setLetterboxBackgroundType(letterboxBackgroundType);
+        mWm.mLetterboxConfiguration.setLetterboxBackgroundTypeOverride(letterboxBackgroundType);
         return mWm.isLetterboxBackgroundMultiColored();
     }
 }