I'd like to hear the story on how he went from the Air Force to the Army, or vice-versa.
Would be interesting.
Not certain about his story, but any academy is a source for commissioning in any of the 4 DoD branches, not just their primary sponsor.
Once upon a time, an academy graduate whose father was from another service could receive a commission in that service, sort of professional courtesy. It was rare and perhaps even more rare these days. A few others transfer to another service after some passage of time.
Billy Mitchell (real name), USMA Class of ?? served with the 1st Infantry Division in Vietnam as an Infantry Platoon Leader. He served a second tour as a Captain, advisor to a Vietnamese Ranger Battalion. After that tour, he was assigned to the Florida Ranger Camp at Eglin AFB. He tried to get into Army flight school, but they had plenty of teenaged Warrant Officers, so no deal. Some Air Force friends told him that the USAF was desperate for pilots and he asked for a transfer and flight school. The USAF said yes, and he served a third tour driving an F4. I met him in Europe when he was flying F15’s.
Years ago, I worked with a former Marine Corps Intelligence Officer (MOS 0202) who was an Air Force Academy graduate. When asked the obvious question about the dissonance between his alma mater and service, he said that graduates of the three U.S. military academies have the option of selecting the branch of the armed forces they want to serve in. The vast majority go on to serve with their academy’s sponsoring service but occasionally one selects a different branch.
I also recall having an officer candidate from the US Military Academy at West Point in our Platoon Leaders Combined (PLC) Combined Course the summer I went to Officer Candidates School at Quantico. (Several decades ago now.)
Maybe like this guy.
http://www.military.com/daily-news/2014/11/12/fort-bragg-airman-to-receive-2nd-silver-star.html