diff --git a/lib/compat/wordpress-6.0/class-wp-theme-json-resolver-6-0.php b/lib/compat/wordpress-6.0/class-wp-theme-json-resolver-6-0.php
index b85e8e335037af..86ca0f683a1a3e 100644
--- a/lib/compat/wordpress-6.0/class-wp-theme-json-resolver-6-0.php
+++ b/lib/compat/wordpress-6.0/class-wp-theme-json-resolver-6-0.php
@@ -258,6 +258,56 @@ public static function get_user_data() {
 		return static::$user;
 	}
 
+	/**
+	 * Gets the styles for blocks from the block.json file.
+	 *
+	 * @return WP_Theme_JSON
+	 */
+	public static function get_block_data() {
+		$registry = WP_Block_Type_Registry::get_instance();
+		$blocks   = $registry->get_all_registered();
+		$config   = array( 'version' => 1 );
+		foreach ( $blocks as $block_name => $block_type ) {
+			if ( is_array( $block_type->style ) ) {
+				foreach ( $block_type->style as $style_override_maybe ) {
+					if ( is_array( $style_override_maybe ) ) {
+						$config['styles']['blocks'][ $block_name ] = static::remove_JSON_comments( $style_override_maybe );
+					}
+				}
+			}
+
+			if (
+				isset( $block_type->supports['spacing']['blockGap']['__experimentalDefault'] ) &&
+				null === _wp_array_get( $config, array( 'styles', 'blocks', $block_name, 'spacing', 'blockGap' ), null )
+			) {
+				// Ensure an empty placeholder value exists for the block, if it provides a default blockGap value.
+				// The real blockGap value to be used will be determined when the styles are rendered for output.
+				$config['styles']['blocks'][ $block_name ]['spacing']['blockGap'] = null;
+			}
+		}
+
+		// Core here means it's the lower level part of the styles chain.
+		// It can be a core or a third-party block.
+		return new WP_Theme_JSON_Gutenberg( $config, 'core' );
+	}
+
+	/**
+	 * When given an array, this will remove any keys with the name `//`.
+	 *
+	 * @param array $array The array to filter.
+	 * @return array The filtered array.
+	 */
+	private static function remove_JSON_comments( $array ) {
+		unset( $array['//'] );
+		foreach ( $array as $k => $v ) {
+			if ( is_array( $v ) ) {
+				$array[ $k ] = static::remove_JSON_comments( $v );
+			}
+		}
+
+		return $array;
+	}
+
 	/**
 	 * There are three sources of data (origins) for a site:
 	 * default, theme, and custom. The custom's has higher priority
diff --git a/lib/compat/wordpress-6.0/client-assets.php b/lib/compat/wordpress-6.0/client-assets.php
index 0c5697817a94a8..a0487c5c7f7ffc 100644
--- a/lib/compat/wordpress-6.0/client-assets.php
+++ b/lib/compat/wordpress-6.0/client-assets.php
@@ -61,11 +61,27 @@ function gutenberg_resolve_assets() {
 
 	foreach ( $block_registry->get_all_registered() as $block_type ) {
 		if ( ! empty( $block_type->style ) ) {
-			$style_handles[] = $block_type->style;
+			if ( is_array( $block_type->style ) ) {
+				foreach ( $block_type->style as $single_style ) {
+					if ( is_string( $single_style ) ) {
+						$style_handles[] = $single_style;
+					}
+				}
+			} else {
+				$style_handles[] = $block_type->style;
+			}
 		}
 
 		if ( ! empty( $block_type->editor_style ) ) {
-			$style_handles[] = $block_type->editor_style;
+			if ( is_array( $block_type->editor_style ) ) {
+				foreach ( $block_type->editor_style as $single_style ) {
+					if ( is_string( $single_style ) ) {
+						$style_handles[] = $single_style;
+					}
+				}
+			} else {
+				$style_handles[] = $block_type->editor_style;
+			}
 		}
 
 		if ( ! empty( $block_type->script ) ) {
diff --git a/lib/compat/wordpress-6.1/blocks.php b/lib/compat/wordpress-6.1/blocks.php
index ed41c5aa8cd098..8949362860f21c 100644
--- a/lib/compat/wordpress-6.1/blocks.php
+++ b/lib/compat/wordpress-6.1/blocks.php
@@ -178,3 +178,68 @@ function gutenberg_block_type_metadata_multiple_view_scripts( $metadata ) {
 	return $metadata;
 }
 add_filter( 'block_type_metadata', 'gutenberg_block_type_metadata_multiple_view_scripts' );
+
+/**
+ * Allow multiple block styles.
+ *
+ * @since 5.9.0
+ *
+ * @param array $metadata Metadata for registering a block type.
+ *
+ * @return array
+ */
+function gutenberg_multiple_block_styles_compat_6_1( $metadata ) {
+	foreach ( array( 'style', 'editorStyle' ) as $key ) {
+		if ( ! empty( $metadata[ $key ] ) && is_array( $metadata[ $key ] ) ) {
+			foreach ( $metadata[ $key ] as $handle ) {
+				// Do not enqueue style arrays such as { "color": { "text": "#fff" } }.
+				if ( is_array( $handle ) ) {
+					continue;
+				}
+
+				$args = array( 'handle' => $handle );
+				if ( 0 === strpos( $handle, 'file:' ) && isset( $metadata['file'] ) ) {
+					$style_path      = remove_block_asset_path_prefix( $handle );
+					$theme_path_norm = wp_normalize_path( get_theme_file_path() );
+					$style_path_norm = wp_normalize_path( realpath( dirname( $metadata['file'] ) . '/' . $style_path ) );
+					$is_theme_block  = isset( $metadata['file'] ) && 0 === strpos( $metadata['file'], $theme_path_norm );
+
+					$style_uri = plugins_url( $style_path, $metadata['file'] );
+
+					if ( $is_theme_block ) {
+						$style_uri = get_theme_file_uri( str_replace( $theme_path_norm, '', $style_path_norm ) );
+					}
+
+					$args = array(
+						'handle' => sanitize_key( "{$metadata['name']}-{$style_path}" ),
+						'src'    => $style_uri,
+					);
+				}
+
+				wp_enqueue_block_style( $metadata['name'], $args );
+			}
+		}
+	}
+	return $metadata;
+}
+
+/*
+ * Priority 11 is used to ensure this runs *after* _wp_multiple_block_styles.
+ *
+ * The order of execution matters in WordPress 6.0 where style arrays such as below are unsupported:
+ *
+ * {
+ *  "style": [ "wp-block-button", {
+ *  		"border": {
+ *  				"radius": "9999px"
+ *  		}
+ *  } ]
+ * }
+ *
+ * _wp_multiple_block_styles flattens the above definition to just {"style": "wp-block-button"} which
+ * is supported in WordPress 6.0.
+ *
+ * In WordPress 6.1, _wp_multiple_block_styles is deprecated and doesn't do anything so the full style
+ * definition is preserved in block metadata for further processing in the theme resolver.
+ */
+add_filter( 'block_type_metadata', 'gutenberg_multiple_block_styles_compat_6_1', 11 );
diff --git a/lib/experimental/class-wp-theme-json-resolver-gutenberg.php b/lib/experimental/class-wp-theme-json-resolver-gutenberg.php
index a4d4e4dfc7066d..7d5fcb637ec989 100644
--- a/lib/experimental/class-wp-theme-json-resolver-gutenberg.php
+++ b/lib/experimental/class-wp-theme-json-resolver-gutenberg.php
@@ -99,52 +99,6 @@ public static function get_theme_data( $deprecated = array(), $settings = array(
 		return $with_theme_supports;
 	}
 
-	/**
-	 * Gets the styles for blocks from the block.json file.
-	 *
-	 * @return WP_Theme_JSON
-	 */
-	public static function get_block_data() {
-		$registry = WP_Block_Type_Registry::get_instance();
-		$blocks   = $registry->get_all_registered();
-		$config   = array( 'version' => 1 );
-		foreach ( $blocks as $block_name => $block_type ) {
-			if ( isset( $block_type->supports['__experimentalStyle'] ) ) {
-				$config['styles']['blocks'][ $block_name ] = static::remove_JSON_comments( $block_type->supports['__experimentalStyle'] );
-			}
-
-			if (
-				isset( $block_type->supports['spacing']['blockGap']['__experimentalDefault'] ) &&
-				null === _wp_array_get( $config, array( 'styles', 'blocks', $block_name, 'spacing', 'blockGap' ), null )
-			) {
-				// Ensure an empty placeholder value exists for the block, if it provides a default blockGap value.
-				// The real blockGap value to be used will be determined when the styles are rendered for output.
-				$config['styles']['blocks'][ $block_name ]['spacing']['blockGap'] = null;
-			}
-		}
-
-		// Core here means it's the lower level part of the styles chain.
-		// It can be a core or a third-party block.
-		return new WP_Theme_JSON_Gutenberg( $config, 'core' );
-	}
-
-	/**
-	 * When given an array, this will remove any keys with the name `//`.
-	 *
-	 * @param array $array The array to filter.
-	 * @return array The filtered array.
-	 */
-	private static function remove_JSON_comments( $array ) {
-		unset( $array['//'] );
-		foreach ( $array as $k => $v ) {
-			if ( is_array( $v ) ) {
-				$array[ $k ] = static::remove_JSON_comments( $v );
-			}
-		}
-
-		return $array;
-	}
-
 	/**
 	 * Returns the data merged from multiple origins.
 	 *
diff --git a/packages/block-library/src/button/block.json b/packages/block-library/src/button/block.json
index f86030c7460a57..97bf9a11dbf88c 100644
--- a/packages/block-library/src/button/block.json
+++ b/packages/block-library/src/button/block.json
@@ -96,5 +96,30 @@
 		{ "name": "outline", "label": "Outline" }
 	],
 	"editorStyle": "wp-block-button-editor",
-	"style": "wp-block-button"
+	"style": [
+		"wp-block-button",
+		{
+			"border": {
+				"//": "100% causes an oval, but any explicit but really high value retains the pill shape.",
+				"radius": "9999px"
+			},
+			"color": {
+				"text": "#fff",
+				"background": "#32373c"
+			},
+			"typography": {
+				"fontSize": "1.125em",
+				"textDecoration": "none"
+			},
+			"spacing": {
+				"padding": {
+					"//": "The extra 2px are added to size solids the same as the outline versions.",
+					"top": "calc(0.667em + 2px)",
+					"right": "calc(1.333em + 2px)",
+					"bottom": "calc(0.667em + 2px) !important",
+					"left": "calc(1.333em + 2px)"
+				}
+			}
+		}
+	]
 }
diff --git a/schemas/json/block.json b/schemas/json/block.json
index fd7bd5a06f708e..0dbc5d2f539536 100644
--- a/schemas/json/block.json
+++ b/schemas/json/block.json
@@ -464,7 +464,10 @@
 				{
 					"type": "array",
 					"items": {
-						"type": "string"
+						"oneOf": [
+							{ "type": "string" },
+							{ "type": "object" }
+						]
 					}
 				}
 			]
@@ -478,7 +481,10 @@
 				{
 					"type": "array",
 					"items": {
-						"type": "string"
+						"oneOf": [
+							{ "type": "string" },
+							{ "type": "object" }
+						]
 					}
 				}
 			]