They'll Probably Find You Out
I was in the Military Intelligence in the Army. One of MI's major responsibilities was conducting background investigations with respect to requests for security clearances and periodic re-investigations of those with security clearances. Almost every sensitive job in the military requires security clearances. Whether you think they are necessary or not -- the military certainly does. And if you try to avoid a position that requires a security clearance you will only shine a spotlight on yourself and trigger a background investigation.
You mention that your family and fraternity brothers are aware of your CD past. You can rest assured, that at some point in your military career one or more of them will be interviewed under oath. The chance that you will be able to close out your career in the military successfully - even should you 100% repress it during your time (and you have indicated that that is not your plan) - is slim to none. When it comes out, as it undoubtedly will, you will end up being dishonorably discharged and find your life in ruins. You, my friend, are playing with a form of fire you can't even begin to understand. Just don't do it The intelligence services are far more capable than you may think.
When I went into the military I also 100% repressed it, but unlike you, no one in the world knew about it before I went in. I had to go in because it was the era when everyone served after their 2-S deferment ran out who didn't either dodge the draft, get married or became a teacher (all forms of dodging, in my opinion). Listen to and heed the advice of your sisters in spirit here who have been through that mill.