diff --git a/packages/backend/src/mfm/to-html.ts b/packages/backend/src/mfm/to-html.ts
index 7c941892f..54e93964b 100644
--- a/packages/backend/src/mfm/to-html.ts
+++ b/packages/backend/src/mfm/to-html.ts
@@ -3,8 +3,9 @@ import type * as mfm from "mfm-js";
 import config from "@/config/index.js";
 import { intersperse } from "@/prelude/array.js";
 import type { IMentionedRemoteUsers } from "@/models/entities/note.js";
+import { resolveMentionWithFallback } from "@/remote/resolve-user.js";
 
-export function toHtml(
+export async function toHtml(
 	nodes: mfm.MfmNode[] | null,
 	mentionedRemoteUsers: IMentionedRemoteUsers = [],
 ) {
@@ -16,9 +17,9 @@ export function toHtml(
 
 	const doc = window.document;
 
-	function appendChildren(children: mfm.MfmNode[], targetElement: any): void {
+	async function appendChildren(children: mfm.MfmNode[], targetElement: any): Promise<void> {
 		if (children) {
-			for (const child of children.map((x) => (handlers as any)[x.type](x)))
+			for (const child of await Promise.all(children.map(async (x) => await (handlers as any)[x.type](x))))
 				targetElement.appendChild(child);
 		}
 	}
@@ -26,33 +27,33 @@ export function toHtml(
 	const handlers: {
 		[K in mfm.MfmNode["type"]]: (node: mfm.NodeType<K>) => any;
 	} = {
-		bold(node) {
+		async bold(node) {
 			const el = doc.createElement("b");
-			appendChildren(node.children, el);
+			await appendChildren(node.children, el);
 			return el;
 		},
 
-		small(node) {
+		async small(node) {
 			const el = doc.createElement("small");
-			appendChildren(node.children, el);
+			await appendChildren(node.children, el);
 			return el;
 		},
 
-		strike(node) {
+		async strike(node) {
 			const el = doc.createElement("del");
-			appendChildren(node.children, el);
+			await appendChildren(node.children, el);
 			return el;
 		},
 
-		italic(node) {
+		async italic(node) {
 			const el = doc.createElement("i");
-			appendChildren(node.children, el);
+			await appendChildren(node.children, el);
 			return el;
 		},
 
-		fn(node) {
+		async fn(node) {
 			const el = doc.createElement("i");
-			appendChildren(node.children, el);
+			await appendChildren(node.children, el);
 			return el;
 		},
 
@@ -64,9 +65,9 @@ export function toHtml(
 			return pre;
 		},
 
-		center(node) {
+		async center(node) {
 			const el = doc.createElement("div");
-			appendChildren(node.children, el);
+			await appendChildren(node.children, el);
 			return el;
 		},
 
@@ -104,28 +105,20 @@ export function toHtml(
 			return el;
 		},
 
-		link(node) {
+		async link(node) {
 			const a = doc.createElement("a");
 			a.href = node.props.url;
-			appendChildren(node.children, a);
+			await appendChildren(node.children, a);
 			return a;
 		},
 
-		mention(node) {
+		async mention(node) {
 			const el = doc.createElement("span");
 			el.setAttribute("class", "h-card");
 			el.setAttribute("translate", "no");
 			const a = doc.createElement("a");
 			const { username, host, acct } = node.props;
-			const remoteUserInfo = mentionedRemoteUsers.find(
-				(remoteUser) =>
-					remoteUser.username.toLowerCase() === username.toLowerCase() && remoteUser.host === host,
-			);
-			a.href = remoteUserInfo
-				? remoteUserInfo.url
-					? remoteUserInfo.url
-					: remoteUserInfo.uri
-				: `${config.url}/${acct}`;
+			a.href = await resolveMentionWithFallback(username, host, acct, mentionedRemoteUsers);
 			a.className = "u-url mention";
 			const span = doc.createElement("span");
 			span.textContent = username;
@@ -135,9 +128,9 @@ export function toHtml(
 			return el;
 		},
 
-		quote(node) {
+		async quote(node) {
 			const el = doc.createElement("blockquote");
-			appendChildren(node.children, el);
+			await appendChildren(node.children, el);
 			return el;
 		},
 
@@ -168,14 +161,14 @@ export function toHtml(
 			return a;
 		},
 
-		plain(node) {
+		async plain(node) {
 			const el = doc.createElement("span");
-			appendChildren(node.children, el);
+			await appendChildren(node.children, el);
 			return el;
 		},
 	};
 
-	appendChildren(nodes, doc.body);
+	await appendChildren(nodes, doc.body);
 
 	return `<p>${doc.body.innerHTML}</p>`;
 }
diff --git a/packages/backend/src/remote/activitypub/misc/get-note-html.ts b/packages/backend/src/remote/activitypub/misc/get-note-html.ts
index cb5294f73..046d60d1a 100644
--- a/packages/backend/src/remote/activitypub/misc/get-note-html.ts
+++ b/packages/backend/src/remote/activitypub/misc/get-note-html.ts
@@ -2,7 +2,7 @@ import * as mfm from "mfm-js";
 import type { Note } from "@/models/entities/note.js";
 import { toHtml } from "../../../mfm/to-html.js";
 
-export default function (note: Note) {
+export default async function (note: Note) {
 	if (!note.text) return "";
 	return toHtml(mfm.parse(note.text), JSON.parse(note.mentionedRemoteUsers));
 }
diff --git a/packages/backend/src/remote/activitypub/renderer/note.ts b/packages/backend/src/remote/activitypub/renderer/note.ts
index 2ad2fec9f..cca291463 100644
--- a/packages/backend/src/remote/activitypub/renderer/note.ts
+++ b/packages/backend/src/remote/activitypub/renderer/note.ts
@@ -108,7 +108,7 @@ export default async function renderNote(
 
 	const summary = note.cw === "" ? String.fromCharCode(0x200b) : note.cw;
 
-	const content = toHtml(
+	const content = await toHtml(
 		Object.assign({}, note, {
 			text: apText,
 		}),
diff --git a/packages/backend/src/remote/activitypub/renderer/person.ts b/packages/backend/src/remote/activitypub/renderer/person.ts
index 7905653a2..5e010d733 100644
--- a/packages/backend/src/remote/activitypub/renderer/person.ts
+++ b/packages/backend/src/remote/activitypub/renderer/person.ts
@@ -73,7 +73,7 @@ export async function renderPerson(user: ILocalUser) {
 		preferredUsername: user.username,
 		name: user.name,
 		summary: profile.description
-			? toHtml(mfm.parse(profile.description))
+			? await toHtml(mfm.parse(profile.description))
 			: null,
 		icon: avatar ? renderImage(avatar) : null,
 		image: banner ? renderImage(banner) : null,
diff --git a/packages/backend/src/remote/resolve-user.ts b/packages/backend/src/remote/resolve-user.ts
index b60106e28..e96f3c316 100644
--- a/packages/backend/src/remote/resolve-user.ts
+++ b/packages/backend/src/remote/resolve-user.ts
@@ -3,12 +3,13 @@ import chalk from "chalk";
 import { IsNull } from "typeorm";
 import config from "@/config/index.js";
 import type { User, IRemoteUser } from "@/models/entities/user.js";
-import { Users } from "@/models/index.js";
+import { UserProfiles, Users } from "@/models/index.js";
 import { toPuny } from "@/misc/convert-host.js";
 import webFinger from "./webfinger.js";
 import { createPerson, updatePerson } from "./activitypub/models/person.js";
 import { remoteLogger } from "./logger.js";
 import { Cache } from "@/misc/cache.js";
+import { IMentionedRemoteUsers } from "@/models/entities/note.js";
 
 const logger = remoteLogger.createSubLogger("resolve-user");
 const uriHostCache = new Cache<string>("resolveUserUriHost", 60 * 60 * 24);
@@ -173,6 +174,21 @@ export async function resolveUser(
 	return user;
 }
 
+export async function resolveMentionWithFallback(username: string, host: string | null, acct: string, cache: IMentionedRemoteUsers): Promise<string> {
+	const fallback = `${config.url}/${acct}`;
+	const cached = cache.find(r => r.username.toLowerCase() === username.toLowerCase() && r.host === host);
+	if (cached) return cached.url ?? cached.uri;
+	if (host === null) return fallback;
+	try {
+		const user = await resolveUser(username, host);
+		const profile = await UserProfiles.findOneBy({ userId: user.id });
+		return profile?.url ?? user.uri ?? fallback;
+	}
+	catch {
+		return fallback;
+	}
+}
+
 export async function getSubjectHostFromUri(uri: string): Promise<string | null> {
 	try {
 		const acct = subjectToAcct((await webFinger(uri)).subject);
diff --git a/packages/backend/test/mfm.ts b/packages/backend/test/mfm.ts
index 5a42e420d..a4f54c550 100644
--- a/packages/backend/test/mfm.ts
+++ b/packages/backend/test/mfm.ts
@@ -5,16 +5,16 @@ import { toHtml } from "../src/mfm/to-html.js";
 import { fromHtml } from "../src/mfm/from-html.js";
 
 describe("toHtml", () => {
-	it("br", () => {
+	it("br", async () => {
 		const input = "foo\nbar\nbaz";
 		const output = "<p><span>foo<br>bar<br>baz</span></p>";
-		assert.equal(toHtml(mfm.parse(input)), output);
+		assert.equal(await toHtml(mfm.parse(input)), output);
 	});
 
-	it("br alt", () => {
+	it("br alt", async () => {
 		const input = "foo\r\nbar\rbaz";
 		const output = "<p><span>foo<br>bar<br>baz</span></p>";
-		assert.equal(toHtml(mfm.parse(input)), output);
+		assert.equal(await toHtml(mfm.parse(input)), output);
 	});
 });