diff --git a/apps/editing-toolkit/editing-toolkit-plugin/wpcom-global-styles/index.php b/apps/editing-toolkit/editing-toolkit-plugin/wpcom-global-styles/index.php
index fcaddb2957668..a1334056436b4 100644
--- a/apps/editing-toolkit/editing-toolkit-plugin/wpcom-global-styles/index.php
+++ b/apps/editing-toolkit/editing-toolkit-plugin/wpcom-global-styles/index.php
@@ -117,10 +117,14 @@ function wpcom_block_global_styles_frontend( $theme_json ) {
 		return $theme_json;
 	}
 
-	if ( class_exists( 'WP_Theme_JSON_Data' ) ) {
-		return new WP_Theme_JSON_Data( array(), 'custom' );
-	} elseif ( class_exists( 'WP_Theme_JSON_Data_Gutenberg' ) ) {
+	/*
+	 * Because Gutenberg overrides Core, the order in which we check the existence of
+	 * the classes below is important in order to give Gutenberg priority if available.
+	 */
+	if ( class_exists( 'WP_Theme_JSON_Data_Gutenberg' ) ) {
 		return new WP_Theme_JSON_Data_Gutenberg( array(), 'custom' );
+	} elseif ( class_exists( 'WP_Theme_JSON_Data' ) ) {
+		return new WP_Theme_JSON_Data( array(), 'custom' );
 	}
 
 	/*
@@ -130,7 +134,6 @@ function wpcom_block_global_styles_frontend( $theme_json ) {
 	 */
 	return $theme_json;
 }
-add_filter( 'theme_json_user', 'wpcom_block_global_styles_frontend' );
 add_filter( 'wp_theme_json_data_user', 'wpcom_block_global_styles_frontend' );
 
 /**
@@ -184,7 +187,19 @@ function wpcom_track_global_styles( $blog_id, $post, $updated ) {
  * @return bool Returns true if custom styles are in use.
  */
 function wpcom_global_styles_in_use() {
-	$user_cpt = WP_Theme_JSON_Resolver_Gutenberg::get_user_data_from_wp_global_styles( wp_get_theme() );
+	$current_theme = wp_get_theme();
+
+	/*
+	 * Because Gutenberg overrides Core, the order in which we check the existence of
+	 * the classes below is important in order to give Gutenberg priority if available.
+	 */
+	if ( class_exists( 'WP_Theme_JSON_Resolver_Gutenberg' ) ) {
+		$user_cpt = WP_Theme_JSON_Resolver_Gutenberg::get_user_data_from_wp_global_styles( $current_theme );
+	} elseif ( class_exists( 'WP_Theme_JSON_Resolver' ) ) {
+		$user_cpt = WP_Theme_JSON_Resolver::get_user_data_from_wp_global_styles( $current_theme );
+	} else {
+		return false;
+	}
 
 	if ( ! isset( $user_cpt['post_content'] ) ) {
 		do_action( 'global_styles_log', 'global_styles_not_in_use' );
@@ -286,3 +301,43 @@ function wpcom_display_global_styles_banner_extra_tooltip() {
 	<?php
 }
 add_action( 'launch_bar_extra_tooltip_toggle_global_styles', 'wpcom_display_global_styles_banner_extra_tooltip' );
+
+/**
+ * Invalidates the cached Global Styles after changing them or when previewing them.
+ */
+function wpcom_invalidate_global_styles_cache() {
+	// This is copied from https://github.com/WordPress/gutenberg/blob/0d9d73f3282e4a0bcd4e0400176d65fcbd5dccb8/lib/compat/wordpress-6.0/class-wp-theme-json-resolver-6-0.php#L171-L186.
+	$args = array(
+		'numberposts' => 1,
+		'orderby'     => 'date',
+		'order'       => 'desc',
+		'post_type'   => 'wp_global_styles',
+		'post_status' => array( 'publish' ),
+		'tax_query'   => array(
+			array(
+				'taxonomy' => 'wp_theme',
+				'field'    => 'name',
+				'terms'    => wp_get_theme()->get_stylesheet(),
+			),
+		),
+	);
+	// phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.serialize_serialize -- needed to mimic Core behavior.
+	$core_global_styles_cache_key = sprintf( 'wp_global_styles_%s', md5( serialize( $args ) ) );
+
+	// This is copied from https://github.com/WordPress/gutenberg/blob/9ff5888a1fcd5aa218cbdab5e58c09953bd9bd8b/lib/compat/wordpress-6.1/get-global-styles-and-settings.php#L78.
+	$gutenberg_global_styles_transient_name = 'gutenberg_global_styles_' . get_stylesheet();
+
+	if ( wpcom_is_previewing_global_styles() && wpcom_should_limit_global_styles() ) {
+		add_filter( 'pre_transient_' . $gutenberg_global_styles_transient_name, '__return_null' );
+		add_filter( 'pre_set_transient_' . $gutenberg_global_styles_transient_name, '__return_false' );
+	}
+
+	add_action(
+		'save_post_wp_global_styles',
+		function () use ( $core_global_styles_cache_key, $gutenberg_global_styles_transient_name ) {
+			wp_cache_delete( $core_global_styles_cache_key );
+			delete_transient( $gutenberg_global_styles_transient_name );
+		}
+	);
+}
+add_action( 'init', 'wpcom_invalidate_global_styles_cache' );