Yes, non-competes for a reasonable time, geographic area, and job-related scope are enforceable in Michigan.
DISCLAIMER: This answer is provided for general informational purposes only, is not intended as legal advice, and does not create an attorney-client relationship. Undisclosed information will alter any answer provided. Do not rely on this information – it is a starting point for your issue and you should contact a licensed attorney in your jurisdiction.
In addition to the great responses provided by Mr. Putzig and Mr. Hutchinson, you may want to review the post below that discuss in more detail Michigan non-compete law. Best to you going forward.
I'm licensed to practice law in Michigan (www.shinnlegal.com) and I primarly focus on employment law and litigation. My office is located in Keego Harbor, MI. My response is provided only to educate the public about general issues that should be discussed with competent legal counsel in your state. Under no circumstances should you consider my response as a substitute for consulting an attorney in order to fully understand how the law may apply to your specific and unique circumstances.