diff --git a/packages/SystemUI/res/values/dimens.xml b/packages/SystemUI/res/values/dimens.xml
index 082ede382c363..2663ffb1fed94 100644
--- a/packages/SystemUI/res/values/dimens.xml
+++ b/packages/SystemUI/res/values/dimens.xml
@@ -1553,6 +1553,9 @@
     <dimen name="status_bar_user_chip_end_margin">12dp</dimen>
     <dimen name="status_bar_user_chip_text_size">12sp</dimen>
 
+    <!-- System UI Dialog -->
+    <dimen name="dialog_title_text_size">24sp</dimen>
+
     <!-- Internet panel related dimensions -->
     <dimen name="internet_dialog_list_max_height">662dp</dimen>
     <!-- The height of the WiFi network in Internet panel. -->
diff --git a/packages/SystemUI/res/values/styles.xml b/packages/SystemUI/res/values/styles.xml
index a3655c31fde9a..8a86fd560655a 100644
--- a/packages/SystemUI/res/values/styles.xml
+++ b/packages/SystemUI/res/values/styles.xml
@@ -1041,7 +1041,7 @@
 
     <style name="TextAppearance.Dialog.Title" parent="@android:style/TextAppearance.DeviceDefault.Large">
         <item name="android:textColor">?android:attr/textColorPrimary</item>
-        <item name="android:textSize">24sp</item>
+        <item name="android:textSize">@dimen/dialog_title_text_size</item>
         <item name="android:fontFamily">@*android:string/config_headlineFontFamily</item>
         <item name="android:lineHeight">32sp</item>
         <item name="android:gravity">center</item>
diff --git a/packages/SystemUI/src/com/android/systemui/accessibility/fontscaling/FontScalingDialog.kt b/packages/SystemUI/src/com/android/systemui/accessibility/fontscaling/FontScalingDialog.kt
index 1836ce8577835..c9579d5e13567 100644
--- a/packages/SystemUI/src/com/android/systemui/accessibility/fontscaling/FontScalingDialog.kt
+++ b/packages/SystemUI/src/com/android/systemui/accessibility/fontscaling/FontScalingDialog.kt
@@ -21,6 +21,7 @@ import android.content.pm.ActivityInfo
 import android.content.res.Configuration
 import android.os.Bundle
 import android.provider.Settings
+import android.util.TypedValue
 import android.view.LayoutInflater
 import android.widget.Button
 import android.widget.SeekBar
@@ -49,8 +50,7 @@ class FontScalingDialog(
     private lateinit var seekBarWithIconButtonsView: SeekBarWithIconButtonsView
     private var lastProgress: Int = -1
 
-    private val configuration: Configuration =
-        Configuration(context.getResources().getConfiguration())
+    private val configuration: Configuration = Configuration(context.resources.configuration)
 
     override fun onCreate(savedInstanceState: Bundle?) {
         setTitle(R.string.font_scaling_dialog_title)
@@ -84,31 +84,45 @@ class FontScalingDialog(
 
         seekBarWithIconButtonsView.setOnSeekBarChangeListener(
             object : OnSeekBarChangeListener {
+                var isTrackingTouch = false
+
                 override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
-                    if (progress != lastProgress) {
-                        if (!fontSizeHasBeenChangedFromTile) {
-                            backgroundExecutor.execute { updateSecureSettingsIfNeeded() }
-                            fontSizeHasBeenChangedFromTile = true
-                        }
-
-                        backgroundExecutor.execute { updateFontScale(strEntryValues[progress]) }
-
-                        lastProgress = progress
+                    if (!isTrackingTouch) {
+                        // The seekbar progress is changed by icon buttons
+                        changeFontSize(progress)
+                    } else {
+                        // Provide preview configuration for text instead of changing the system
+                        // font scale before users release their finger from the seekbar.
+                        createTextPreview(progress)
                     }
                 }
 
                 override fun onStartTrackingTouch(seekBar: SeekBar) {
-                    // Do nothing
+                    isTrackingTouch = true
                 }
 
                 override fun onStopTrackingTouch(seekBar: SeekBar) {
-                    // Do nothing
+                    isTrackingTouch = false
+                    changeFontSize(seekBar.progress)
                 }
             }
         )
         doneButton.setOnClickListener { dismiss() }
     }
 
+    private fun changeFontSize(progress: Int) {
+        if (progress != lastProgress) {
+            if (!fontSizeHasBeenChangedFromTile) {
+                backgroundExecutor.execute { updateSecureSettingsIfNeeded() }
+                fontSizeHasBeenChangedFromTile = true
+            }
+
+            backgroundExecutor.execute { updateFontScale(strEntryValues[progress]) }
+
+            lastProgress = progress
+        }
+    }
+
     private fun fontSizeValueToIndex(value: Float): Int {
         var lastValue = strEntryValues[0].toFloat()
         for (i in 1 until strEntryValues.size) {
@@ -153,6 +167,20 @@ class FontScalingDialog(
         }
     }
 
+    /** Provides font size preview for text before putting the final settings to the system. */
+    fun createTextPreview(index: Int) {
+        val previewConfig = Configuration(configuration)
+        previewConfig.fontScale = strEntryValues[index].toFloat()
+
+        val previewConfigContext = context.createConfigurationContext(previewConfig)
+        previewConfigContext.theme.setTo(context.theme)
+
+        title.setTextSize(
+            TypedValue.COMPLEX_UNIT_PX,
+            previewConfigContext.resources.getDimension(R.dimen.dialog_title_text_size)
+        )
+    }
+
     companion object {
         private const val ON = "1"
         private const val OFF = "0"
diff --git a/packages/SystemUI/src/com/android/systemui/flags/Flags.kt b/packages/SystemUI/src/com/android/systemui/flags/Flags.kt
index ff4a2528fcde2..27f35db056e90 100644
--- a/packages/SystemUI/src/com/android/systemui/flags/Flags.kt
+++ b/packages/SystemUI/src/com/android/systemui/flags/Flags.kt
@@ -285,7 +285,7 @@ object Flags {
     /** Enables Font Scaling Quick Settings tile */
     // TODO(b/269341316): Tracking Bug
     @JvmField
-    val ENABLE_FONT_SCALING_TILE = unreleasedFlag(509, "enable_font_scaling_tile", teamfood = false)
+    val ENABLE_FONT_SCALING_TILE = unreleasedFlag(509, "enable_font_scaling_tile", teamfood = true)
 
     /** Enables new QS Edit Mode visual refresh */
     // TODO(b/269787742): Tracking Bug
diff --git a/packages/SystemUI/tests/src/com/android/systemui/accessibility/fontscaling/FontScalingDialogTest.kt b/packages/SystemUI/tests/src/com/android/systemui/accessibility/fontscaling/FontScalingDialogTest.kt
index eb8295653199e..353a7c370ab63 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/accessibility/fontscaling/FontScalingDialogTest.kt
+++ b/packages/SystemUI/tests/src/com/android/systemui/accessibility/fontscaling/FontScalingDialogTest.kt
@@ -26,6 +26,8 @@ import com.android.systemui.R
 import com.android.systemui.SysuiTestCase
 import com.android.systemui.common.ui.view.SeekBarWithIconButtonsView
 import com.android.systemui.util.concurrency.FakeExecutor
+import com.android.systemui.util.mockito.capture
+import com.android.systemui.util.mockito.whenever
 import com.android.systemui.util.settings.FakeSettings
 import com.android.systemui.util.settings.SecureSettings
 import com.android.systemui.util.settings.SystemSettings
@@ -34,6 +36,10 @@ import com.google.common.truth.Truth.assertThat
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
+import org.mockito.ArgumentCaptor
+import org.mockito.Captor
+import org.mockito.Mockito.spy
+import org.mockito.Mockito.verify
 import org.mockito.MockitoAnnotations
 
 private const val ON: Int = 1
@@ -53,6 +59,9 @@ class FontScalingDialogTest : SysuiTestCase() {
             .getResources()
             .getStringArray(com.android.settingslib.R.array.entryvalues_font_size)
 
+    @Captor
+    private lateinit var seekBarChangeCaptor: ArgumentCaptor<SeekBar.OnSeekBarChangeListener>
+
     @Before
     fun setUp() {
         MockitoAnnotations.initMocks(this)
@@ -61,7 +70,7 @@ class FontScalingDialogTest : SysuiTestCase() {
         secureSettings = FakeSettings()
         backgroundExecutor = FakeExecutor(FakeSystemClock())
         fontScalingDialog =
-            FontScalingDialog(mContext, systemSettings, secureSettings, backgroundExecutor)
+            spy(FontScalingDialog(mContext, systemSettings, secureSettings, backgroundExecutor))
     }
 
     @Test
@@ -70,7 +79,7 @@ class FontScalingDialogTest : SysuiTestCase() {
 
         val seekBar: SeekBar = fontScalingDialog.findViewById<SeekBar>(R.id.seekbar)!!
         val progress: Int = seekBar.getProgress()
-        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def = */ 1.0f)
+        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
 
         assertThat(currentScale).isEqualTo(fontSizeValueArray[progress].toFloat())
 
@@ -91,7 +100,7 @@ class FontScalingDialogTest : SysuiTestCase() {
         iconEndFrame.performClick()
         backgroundExecutor.runAllReady()
 
-        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def = */ 1.0f)
+        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
         assertThat(seekBar.getProgress()).isEqualTo(1)
         assertThat(currentScale).isEqualTo(fontSizeValueArray[1].toFloat())
 
@@ -112,7 +121,7 @@ class FontScalingDialogTest : SysuiTestCase() {
         iconStartFrame.performClick()
         backgroundExecutor.runAllReady()
 
-        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def = */ 1.0f)
+        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
         assertThat(seekBar.getProgress()).isEqualTo(fontSizeValueArray.size - 2)
         assertThat(currentScale)
             .isEqualTo(fontSizeValueArray[fontSizeValueArray.size - 2].toFloat())
@@ -141,4 +150,64 @@ class FontScalingDialogTest : SysuiTestCase() {
 
         fontScalingDialog.dismiss()
     }
+
+    @Test
+    fun dragSeekbar_systemFontSizeSettingsDoesNotChange() {
+        val slider: SeekBarWithIconButtonsView = spy(SeekBarWithIconButtonsView(mContext))
+        whenever(
+                fontScalingDialog.findViewById<SeekBarWithIconButtonsView>(R.id.font_scaling_slider)
+            )
+            .thenReturn(slider)
+        fontScalingDialog.show()
+        verify(slider).setOnSeekBarChangeListener(capture(seekBarChangeCaptor))
+        val seekBar: SeekBar = slider.findViewById(R.id.seekbar)!!
+
+        // Default seekbar progress for font size is 1, simulate dragging to 0 without
+        // releasing the finger.
+        seekBarChangeCaptor.value.onStartTrackingTouch(seekBar)
+        // Update seekbar progress. This will trigger onProgressChanged in the
+        // OnSeekBarChangeListener and the seekbar could get updated progress value
+        // in onStopTrackingTouch.
+        seekBar.progress = 0
+        backgroundExecutor.runAllReady()
+
+        // Verify that the scale of font size remains the default value 1.0f.
+        var systemScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
+        assertThat(systemScale).isEqualTo(1.0f)
+
+        // Simulate releasing the finger from the seekbar.
+        seekBarChangeCaptor.value.onStopTrackingTouch(seekBar)
+        backgroundExecutor.runAllReady()
+
+        // Verify that the scale of font size has been updated.
+        systemScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
+        assertThat(systemScale).isEqualTo(fontSizeValueArray[0].toFloat())
+
+        fontScalingDialog.dismiss()
+    }
+
+    @Test
+    fun dragSeekBar_createTextPreview() {
+        val slider: SeekBarWithIconButtonsView = spy(SeekBarWithIconButtonsView(mContext))
+        whenever(
+                fontScalingDialog.findViewById<SeekBarWithIconButtonsView>(R.id.font_scaling_slider)
+            )
+            .thenReturn(slider)
+        fontScalingDialog.show()
+        verify(slider).setOnSeekBarChangeListener(capture(seekBarChangeCaptor))
+        val seekBar: SeekBar = slider.findViewById(R.id.seekbar)!!
+
+        // Default seekbar progress for font size is 1, simulate dragging to 0 without
+        // releasing the finger
+        seekBarChangeCaptor.value.onStartTrackingTouch(seekBar)
+        seekBarChangeCaptor.value.onProgressChanged(
+            seekBar,
+            /* progress= */ 0,
+            /* fromUser= */ false
+        )
+        backgroundExecutor.runAllReady()
+
+        verify(fontScalingDialog).createTextPreview(/* index= */ 0)
+        fontScalingDialog.dismiss()
+    }
 }