If by Allied positions you count the Budeswehr - the post-war German armed forces - it was quite common. For example, several German aces from the war found positions in the new German Air Force. Günther Rall, a Bf 109 ace who mainly fought on the Eastern Front, rose as high as Inspector of the Air Force in the 1970s and held the rank Lieutenant General. The German Army was similarly led by many men who had served in WWII, even in very high positions. The Army's first Chief of Staff was Hans Röttiger, who had been a general in the Wehrmacht during WWII. The US and NATO had no issues working with men such as Röttiger and Rall, clearly, and indeed worked to integrate members of the WWII Wehrmacht officer corps into the newly founded Bundeswehr in order to create a capable armed forces.

There was one that I remember, though I don't remember where I heard it, that being of Adolf Heusinger later becoming the Chairman of the NATO Military Committee.

Here's a link to someone's work on that topic here

Credit to u/kieslowskifan

there is also, the U.S. taking in German scientists and integrated into nasa