diff --git a/changelog_unreleased/typescript/18522.md b/changelog_unreleased/typescript/18522.md
new file mode 100644
index 000000000..38548d5f0
--- /dev/null
+++ b/changelog_unreleased/typescript/18522.md
@@ -0,0 +1,35 @@
+#### Fix line comments jumping past member expression lookups (#18522 by @ulrichstark)
+
+Line comments between a member expression object and property were incorrectly moved past subsequent content like `as` expressions.
+
+<!-- prettier-ignore -->
+```tsx
+// Input
+function getClassNameFromPrototypeMethod(container) {
+  return ((container // a
+    .left as PropertyAccessExpression) // b
+    .expression as PropertyAccessExpression) // c
+    .expression; // d
+}
+
+// Prettier stable
+function getClassNameFromPrototypeMethod(container) {
+  return (
+    (
+      container.left as PropertyAccessExpression // a
+    ).expression as PropertyAccessExpression // b
+  ).expression; // c // d
+}
+
+// Prettier main
+function getClassNameFromPrototypeMethod(container) {
+  return (
+    (
+      container // a
+      .left as PropertyAccessExpression
+    ) // b
+    .expression as PropertyAccessExpression
+  ) // c
+  .expression; // d
+}
+```
diff --git a/src/language-js/print/member.js b/src/language-js/print/member.js
index 45773b085..ecc90a4ac 100644
--- a/src/language-js/print/member.js
+++ b/src/language-js/print/member.js
@@ -1,4 +1,10 @@
-import { group, indent, label, softline } from "../../document/index.js";
+import {
+  group,
+  indent,
+  label,
+  lineSuffixBoundary,
+  softline,
+} from "../../document/index.js";
 import {
   getCallArguments,
   isCallExpression,
@@ -62,6 +68,7 @@ function printMemberExpression(path, options, print) {
 
   return label(objectDoc.label, [
     objectDoc,
+    lineSuffixBoundary,
     shouldInline ? lookupDoc : group(indent([softline, lookupDoc])),
   ]);
 }
diff --git a/tests/format/js/template-literals/__snapshots__/format.test.js.snap b/tests/format/js/template-literals/__snapshots__/format.test.js.snap
index f4fa69117..ff0a6ae01 100644
--- a/tests/format/js/template-literals/__snapshots__/format.test.js.snap
+++ b/tests/format/js/template-literals/__snapshots__/format.test.js.snap
@@ -220,7 +220,8 @@ a = \`\${[[1, 2, 3], [4, 5, 6]]}\`
 
 =====================================output=====================================
 const long1 = \`long \${
-  a.b //comment
+  a //comment
+  .b
 } long longlong \${a.b.c.d.e} long longlong \${a.b.c.d.e} long longlong \${a.b.c.d.e} long long\`;
 const long2 = \`long \${a.b.c.d.e} long longlong \${loooooooooooooooooong} long longlong \${loooooooooooooooooong} long longlong \${loooooooooooooooooong} long long\`;
 
diff --git a/tests/format/typescript/as/comments/17407.ts b/tests/format/typescript/as/comments/17407.ts
new file mode 100644
index 000000000..b9dde36fb
--- /dev/null
+++ b/tests/format/typescript/as/comments/17407.ts
@@ -0,0 +1,6 @@
+function getClassNameFromPrototypeMethod(container) {
+  return ((container // a
+    .left as PropertyAccessExpression) // b
+    .expression as PropertyAccessExpression) // c
+    .expression; // d
+}
diff --git a/tests/format/typescript/as/comments/__snapshots__/format.test.js.snap b/tests/format/typescript/as/comments/__snapshots__/format.test.js.snap
index a1d914a13..57bf4733c 100644
--- a/tests/format/typescript/as/comments/__snapshots__/format.test.js.snap
+++ b/tests/format/typescript/as/comments/__snapshots__/format.test.js.snap
@@ -1,5 +1,33 @@
 // Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
+exports[`17407.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript", "flow"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+function getClassNameFromPrototypeMethod(container) {
+  return ((container // a
+    .left as PropertyAccessExpression) // b
+    .expression as PropertyAccessExpression) // c
+    .expression; // d
+}
+
+=====================================output=====================================
+function getClassNameFromPrototypeMethod(container) {
+  return (
+    (
+      container // a
+      .left as PropertyAccessExpression
+    ) // b
+    .expression as PropertyAccessExpression
+  ) // c
+  .expression; // d
+}
+
+================================================================================
+`;
+
 exports[`18160.ts [hermes] format 1`] = `
 "';' expected (7:2)
    5 | comment