diff --git a/wagtail/wagtailadmin/static_src/wagtailadmin/js/page-editor.js b/wagtail/wagtailadmin/static_src/wagtailadmin/js/page-editor.js
index f09834b3a1..99f9f2b663 100644
--- a/wagtail/wagtailadmin/static_src/wagtailadmin/js/page-editor.js
+++ b/wagtail/wagtailadmin/static_src/wagtailadmin/js/page-editor.js
@@ -303,15 +303,19 @@ function cleanForSlug(val, useURLify) {
 }
 
 function initSlugAutoPopulate() {
+    var slugFollowsTitle = false;
+
     $('#id_title').on('focus', function() {
-        $('#id_slug').data('previous-val', $('#id_slug').val());
-        $(this).data('previous-val', $(this).val());
+        /* slug should only follow the title field if its value matched the title's value at the time of focus */
+        var currentSlug = $('#id_slug').val();
+        var slugifiedTitle = cleanForSlug(this.value);
+        slugFollowsTitle = (currentSlug == slugifiedTitle);
     });
 
     $('#id_title').on('keyup keydown keypress blur', function() {
-        if ($('body').hasClass('create') || (!$('#id_slug').data('previous-val').length || cleanForSlug($('#id_title').data('previous-val')) === $('#id_slug').data('previous-val'))) {
-            // only update slug if the page is being created from scratch, if slug is completely blank, or if title and slug prior to typing were identical
-            $('#id_slug').val(cleanForSlug($('#id_title').val()));
+        if (slugFollowsTitle) {
+            var slugifiedTitle = cleanForSlug(this.value);
+            $('#id_slug').val(slugifiedTitle);
         }
     });
 }
@@ -364,7 +368,10 @@ function initCollapsibleBlocks() {
 }
 
 $(function() {
-    initSlugAutoPopulate();
+    /* Only non-live pages should auto-populate the slug from the title */
+    if (!$('body').hasClass('page-is-live')) {
+        initSlugAutoPopulate();
+    }
     initSlugCleaning();
     initErrorDetection();
     initCollapsibleBlocks();
diff --git a/wagtail/wagtailadmin/templates/wagtailadmin/pages/edit.html b/wagtail/wagtailadmin/templates/wagtailadmin/pages/edit.html
index edbcd49a92..c897f11823 100644
--- a/wagtail/wagtailadmin/templates/wagtailadmin/pages/edit.html
+++ b/wagtail/wagtailadmin/templates/wagtailadmin/pages/edit.html
@@ -3,7 +3,7 @@
 {% load gravatar %}
 {% load i18n %}
 {% block titletag %}{% blocktrans with title=page.title page_type=content_type.model_class.get_verbose_name %}Editing {{ page_type }}: {{ title }}{% endblocktrans %}{% endblock %}
-{% block bodyclass %}page-editor model-{{ content_type.model }}{% endblock %}
+{% block bodyclass %}page-editor {% if page.live %}page-is-live{% endif %} model-{{ content_type.model }}{% endblock %}
 
 {% block content %}
     {% page_permissions page as page_perms %}