diff --git a/app/assets/javascripts/discourse/app/components/reviewable-item.js b/app/assets/javascripts/discourse/app/components/reviewable-item.js
index 1e373f2ea87..20553d66b9b 100644
--- a/app/assets/javascripts/discourse/app/components/reviewable-item.js
+++ b/app/assets/javascripts/discourse/app/components/reviewable-item.js
@@ -15,6 +15,7 @@ import ExplainReviewableModal from "discourse/components/modal/explain-reviewabl
 let _components = {};
 
 const pluginReviewableParams = {};
+const actionModalClassMap = {};
 
 export function addPluginReviewableParam(reviewableType, param) {
   pluginReviewableParams[reviewableType]
@@ -22,6 +23,10 @@ export function addPluginReviewableParam(reviewableType, param) {
     : (pluginReviewableParams[reviewableType] = [param]);
 }
 
+export function registerReviewableActionModal(actionName, modalClass) {
+  actionModalClassMap[actionName] = modalClass;
+}
+
 export default Component.extend({
   adminTools: optionalService(),
   dialog: service(),
@@ -273,8 +278,11 @@ export default Component.extend({
       }
 
       const message = performableAction.get("confirm_message");
-      let requireRejectReason = performableAction.get("require_reject_reason");
-      let customModal = performableAction.get("custom_modal");
+      const requireRejectReason = performableAction.get(
+        "require_reject_reason"
+      );
+      const actionModalClass = actionModalClassMap[performableAction.id];
+
       if (message) {
         this.dialog.confirm({
           message,
@@ -288,13 +296,13 @@ export default Component.extend({
           performConfirmed: this._performConfirmed,
           action: performableAction,
         });
-      } else if (customModal) {
-        showModal(customModal, {
-          title: `review.${customModal}.title`,
-          model: this.reviewable,
-        }).setProperties({
-          performConfirmed: this._performConfirmed,
-          action: performableAction,
+      } else if (actionModalClass) {
+        this.modal.show(actionModalClass, {
+          model: {
+            reviewable: this.reviewable,
+            performConfirmed: this._performConfirmed,
+            action: performableAction,
+          },
         });
       } else {
         return this._performConfirmed(performableAction);
diff --git a/app/assets/javascripts/discourse/app/lib/plugin-api.js b/app/assets/javascripts/discourse/app/lib/plugin-api.js
index d7d607b7ca1..4503549ef8d 100644
--- a/app/assets/javascripts/discourse/app/lib/plugin-api.js
+++ b/app/assets/javascripts/discourse/app/lib/plugin-api.js
@@ -55,7 +55,10 @@ import { addGlobalNotice } from "discourse/components/global-notice";
 import { addNavItem } from "discourse/models/nav-item";
 import { addPluginDocumentTitleCounter } from "discourse/components/d-document";
 import { addPluginOutletDecorator } from "discourse/components/plugin-connector";
-import { addPluginReviewableParam } from "discourse/components/reviewable-item";
+import {
+  addPluginReviewableParam,
+  registerReviewableActionModal,
+} from "discourse/components/reviewable-item";
 import {
   addComposerSaveErrorCallback,
   addPopupMenuOptionsCallback,
@@ -130,7 +133,7 @@ import { _addBulkButton } from "discourse/components/modal/topic-bulk-actions";
 // based on Semantic Versioning 2.0.0. Please update the changelog at
 // docs/CHANGELOG-JAVASCRIPT-PLUGIN-API.md whenever you change the version
 // using the format described at https://keepachangelog.com/en/1.0.0/.
-export const PLUGIN_API_VERSION = "1.9.0";
+export const PLUGIN_API_VERSION = "1.10.0";
 
 // This helper prevents us from applying the same `modifyClass` over and over in test mode.
 function canModify(klass, type, resolverName, changes) {
@@ -1648,10 +1651,44 @@ class PluginApi {
   addSaveableUserOptionField(fieldName) {
     addSaveableUserOptionField(fieldName);
   }
+
+  /**
+   * Adds additional params to be sent to the reviewable/:id/perform/:action
+   * endpoint for a given reviewable type. This is so plugins can provide more
+   * complex reviewable actions that may depend on a custom modal.
+   *
+   * This is copied from the reviewable model instance when performing an action
+   * on the ReviewableItem component.
+   *
+   * ```
+   * api.addPluginReviewableParam("ReviewablePluginType", "some_param");
+   * ```
+   **/
   addPluginReviewableParam(reviewableType, param) {
     addPluginReviewableParam(reviewableType, param);
   }
 
+  /**
+   * Registers a mapping between a JavaScript modal component class and a server-side reviewable
+   * action, which is registered via `actions.add` and `build_actions`.
+   *
+   * For more information about modal classes, which are special Ember components used with
+   * the DModal API, see:
+   *
+   * https://meta.discourse.org/t/using-the-dmodal-api-to-render-modal-windows-aka-popups-dialogs-in-discourse/268304.
+   *
+   * @param {String} reviewableAction - The action name, as registered in the server-side.
+   * @param {Class} modalClass - The actual JavaScript class of the modal.
+   *
+   * @example
+   * ```
+   * api.registerReviewableActionModal("approve_category_expert", ExpertGroupChooserModal);
+   * ```
+   **/
+  registerReviewableActionModal(reviewableType, modalClass) {
+    registerReviewableActionModal(reviewableType, modalClass);
+  }
+
   /**
    * Change the default category background and text colors in the
    * category creation modal.
diff --git a/app/serializers/reviewable_action_serializer.rb b/app/serializers/reviewable_action_serializer.rb
index 469164bc26d..d4e09005619 100644
--- a/app/serializers/reviewable_action_serializer.rb
+++ b/app/serializers/reviewable_action_serializer.rb
@@ -8,8 +8,7 @@ class ReviewableActionSerializer < ApplicationSerializer
              :confirm_message,
              :description,
              :client_action,
-             :require_reject_reason,
-             :custom_modal
+             :require_reject_reason
 
   def label
     I18n.t(object.label)
@@ -38,8 +37,4 @@ class ReviewableActionSerializer < ApplicationSerializer
   def include_require_reject_reason?
     object.require_reject_reason.present?
   end
-
-  def include_custom_modal?
-    object.custom_modal.present?
-  end
 end
diff --git a/docs/CHANGELOG-JAVASCRIPT-PLUGIN-API.md b/docs/CHANGELOG-JAVASCRIPT-PLUGIN-API.md
index 0f3cdbfe782..176ea043469 100644
--- a/docs/CHANGELOG-JAVASCRIPT-PLUGIN-API.md
+++ b/docs/CHANGELOG-JAVASCRIPT-PLUGIN-API.md
@@ -7,6 +7,13 @@ in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.10.0] - 2023-08-25
+
+### Added
+
+- Adds `registerReviewableActionModal` which allows core and plugins to register a modal component class
+  which is used to show a modal for certain reviewable actions.
+
 ## [1.9.0] - 2023-08-09
 
 ### Added