diff --git a/.changeset/createjwt-curve-alias.md b/.changeset/createjwt-curve-alias.md
new file mode 100644
index 0000000..17904e2
--- /dev/null
+++ b/.changeset/createjwt-curve-alias.md
@@ -0,0 +1,9 @@
+---
+"@agentcommercekit/jwt": minor
+---
+
+`createJwt` now accepts key-curve names (`secp256k1`, `secp256r1`, `Ed25519`)
+as `alg` aliases and resolves them to their JWT algorithms (`ES256K`, `ES256`,
+`EdDSA`), matching the documented behavior. The alias was documented but never
+wired up, so previously only JWT algorithm names worked. Passing a JWT
+algorithm directly is unchanged.
diff --git a/packages/jwt/src/create-jwt.test.ts b/packages/jwt/src/create-jwt.test.ts
index 5ae2cf8..9221239 100644
--- a/packages/jwt/src/create-jwt.test.ts
+++ b/packages/jwt/src/create-jwt.test.ts
@@ -55,4 +55,34 @@ describe("createJWT", () => {
       "Failed to create JWT",
     )
   })
+
+  const validJwt =
+    "eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NksifQ.eyJpc3MiOiJkaWQ6ZXhhbXBsZTo0NTYifQ.sig"
+
+  it.each([
+    { alg: "secp256k1", expected: "ES256K" },
+    { alg: "secp256r1", expected: "ES256" },
+    { alg: "Ed25519", expected: "EdDSA" },
+  ] as const)(
+    "resolves the key-curve alias $alg to $expected",
+    async ({ alg, expected }) => {
+      vi.mocked(baseCreateJWT).mockResolvedValueOnce(validJwt)
+
+      await createJwt(mockPayload, mockOptions, { alg })
+
+      expect(baseCreateJWT).toHaveBeenCalledWith(mockPayload, mockOptions, {
+        alg: expected,
+      })
+    },
+  )
+
+  it("passes a JWT algorithm through unchanged", async () => {
+    vi.mocked(baseCreateJWT).mockResolvedValueOnce(validJwt)
+
+    await createJwt(mockPayload, mockOptions, { alg: "EdDSA" })
+
+    expect(baseCreateJWT).toHaveBeenCalledWith(mockPayload, mockOptions, {
+      alg: "EdDSA",
+    })
+  })
 })
diff --git a/packages/jwt/src/create-jwt.ts b/packages/jwt/src/create-jwt.ts
index e99d50d..4edd379 100644
--- a/packages/jwt/src/create-jwt.ts
+++ b/packages/jwt/src/create-jwt.ts
@@ -1,3 +1,4 @@
+import type { KeyCurve } from "@agentcommercekit/keys"
 import {
   createJWT as baseCreateJWT,
   type JWTHeader,
@@ -5,7 +6,11 @@ import {
   type JWTPayload,
 } from "did-jwt"
 
-import type { JwtAlgorithm } from "./jwt-algorithm"
+import {
+  curveToJwtAlgorithm,
+  isJwtAlgorithm,
+  type JwtAlgorithm,
+} from "./jwt-algorithm"
 import { isJwtString, type JwtString } from "./jwt-string"
 
 export type JwtPayload = JWTPayload
@@ -25,19 +30,23 @@ export interface JwtHeader extends Omit<JWTHeader, "alg" | "typ"> {
  * @param payload - The payload to create the JWT from
  * @param options - The options to create the JWT from
  * @param header - Optional header overrides
- * @param header.alg - The algorithm to use for the JWT. Accepts `secp256k1` and
- *  `Ed25519` as aliases for `ES256K` and `EdDSA` respectively. Defaults to
+ * @param header.alg - The algorithm to use for the JWT. Accepts a JWT
+ *  algorithm (`ES256`, `ES256K`, `EdDSA`) or a key-curve alias (`secp256k1`,
+ *  `secp256r1`, `Ed25519`) that is resolved to its JWT algorithm. Defaults to
  *  `ES256K`.
  * @returns The JWT
  */
 export async function createJwt(
   payload: Partial<JwtPayload>,
   options: JwtOptions,
-  { alg = "ES256K", ...header }: Partial<JwtHeader> = {},
+  {
+    alg = "ES256K",
+    ...header
+  }: Partial<Omit<JwtHeader, "alg">> & { alg?: JwtAlgorithm | KeyCurve } = {},
 ): Promise<JwtString> {
   const result = await baseCreateJWT(payload, options, {
     ...header,
-    alg,
+    alg: isJwtAlgorithm(alg) ? alg : curveToJwtAlgorithm(alg),
   })
 
   if (!isJwtString(result)) {