diff --git a/changelog/28604.txt b/changelog/28604.txt
new file mode 100644
index 000000000000..9bdc0a5146c6
--- /dev/null
+++ b/changelog/28604.txt
@@ -0,0 +1,3 @@
+```release-note:improvement
+ui: Stretch text field to fit content in JSON editor
+```
diff --git a/ui/app/styles/components/codemirror.scss b/ui/app/styles/components/codemirror.scss
index 49cd9d2d3330..c38280a1144a 100644
--- a/ui/app/styles/components/codemirror.scss
+++ b/ui/app/styles/components/codemirror.scss
@@ -62,6 +62,7 @@ $gutter-grey: #2a2f36;
     font-family: $family-monospace;
     -webkit-font-smoothing: auto;
     line-height: 1.4;
+    height: 100%;
   }
 
   .CodeMirror-gutters {