diff --git a/core/autoload/themes.el b/core/autoload/themes.el
index 13ec82643..bed7c4f37 100644
--- a/core/autoload/themes.el
+++ b/core/autoload/themes.el
@@ -34,7 +34,12 @@ all themes. It will apply to all themes once they are loaded."
                (apply #'custom-theme-set-faces theme
                       (mapcan #'doom--custom-theme-set-face
                               (list ,@specs)))))))
-       (unless doom-theme (funcall #',fn))
+       ;; Apply the changes immediately if the user is using the default theme
+       ;; or the theme has already loaded. This allows you to evaluate these
+       ;; macros on the fly and customize your faces iteratively.
+       (when (or (get 'doom-theme 'previous-themes)
+                 (null doom-theme))
+         (funcall #',fn))
        ;; TODO Append to `doom-load-theme-hook' with DEPTH instead when Emacs
        ;;      26.x support is dropped.
        (add-hook 'doom-customize-theme-hook #',fn 'append))))
diff --git a/core/core-ui.el b/core/core-ui.el
index c996f0532..cc1851e97 100644
--- a/core/core-ui.el
+++ b/core/core-ui.el
@@ -634,13 +634,15 @@ windows, switch to `doom-fallback-buffer'. Otherwise, delegate to original
   ;; buffer-local face remaps (by `mixed-pitch-mode', for instance) won't
   ;; interfere with recalculating faces in new themes.
   (with-temp-buffer
-    ;; Disable previous themes so there are no conflicts. If you truly want
-    ;; multiple themes enabled, then use `enable-theme' instead.
-    (mapc #'disable-theme custom-enabled-themes)
-    (prog1 (funcall orig-fn theme no-confirm no-enable)
-      (when (and (not no-enable) (custom-theme-enabled-p theme))
-        (setq doom-theme theme)
-        (doom-run-hooks 'doom-load-theme-hook)))))
+    (let ((last-themes (copy-sequence custom-enabled-themes)))
+      ;; Disable previous themes so there are no conflicts. If you truly want
+      ;; multiple themes enabled, then use `enable-theme' instead.
+      (mapc #'disable-theme custom-enabled-themes)
+      (prog1 (funcall orig-fn theme no-confirm no-enable)
+        (when (and (not no-enable) (custom-theme-enabled-p theme))
+          (setq doom-theme theme)
+          (put 'doom-theme 'previous-themes last-themes)
+          (doom-run-hooks 'doom-load-theme-hook))))))
 
 
 ;;