I just beat Halo 4 on Legendary and Master Chiefs armor was not unlocked. HOW DO I UNLOCK IT!
Must be connected to love the whole time. And check your campaign commendations for which one you need to complete. It’s under campaign commendations 
It’s the Mark VI armor and you can unlock it by completing the Campaign on Legendary while connected to Xbox Live.
The armor isn’t tied to the achievements but to the commendations, from my understanding. Your commendation record shows that there was some kind of issue with Dawn, Requiem, Forerunner, and Reclaimer (most likely a disconnect, or some other connection issue), rendering their completion invalid for the commendation. Sadly, the only thing to be done about it is to redo the levels again.
> The armor isn’t tied to the achievements but to the commendations, from my understanding. Your commendation record shows that there was some kind of issue with the first four levels(most likely a disconnect, or some other connection issue), rendering their completion invalid for the commendation. Sadly, the only thing to be done about it is to redo the levels again.
This^ what I said but explained clearly and more perfectly
When I complete a mission or challenge I expect the reward. If being connected to Live is a requirement, then say so, and stop the game to let me know I’ve been disconnected and while you are at it, maybe you could try to reconnect me! It’s never been a problem on my side that I can tell. When I discover I’m off line I just tell it to reconnect and presto-chango, I’m back online but without the rewards I was promised.
Unacceptable. This will be the first Halo game I trade in. All The rest are still in my game CD case. You let me down on this one.
> https://forums.halowaypoint.com/yaf_postsm2117971_No-Mark-VI-armor-after-Legendary-Campaign.aspx#post2117971
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> When I complete a mission or challenge I expect the reward. If being connected to Live is a requirement, <mark>then say so</mark>, and stop the game to let me know I’ve been disconnected and while you are at it, maybe you could try to reconnect me! <mark>It’s never been a problem on my side that I can tel</mark>l. When I discover I’m off line I just tell it to reconnect and presto-chango, I’m back online but without the rewards I was promised.
>
> Unacceptable. This will be the first Halo game I trade in. All The rest are still in my game CD case. You let me down on this one.
Look for a large disconnected from Xbox Live sign appearing at the bottom of your screen when this occurs.
The problem WAS on your side, you lost connection to Xbox Live for a unknown reason. You simply ignored the fact, and it did reconnect later, but this happened four missions after you lost connection.
Also, is it really that hard to complete four entertaining missions? You could always add a couple of skulls for the weekly challenge as well.
So looking over the evidence, you kinda let yourself down on this one.