Devine was a Fifth columnist. He used the alias of a partygoer in order to conceal his more dubious activities (kidnapping, blackmail, homicide, smuggling the SA into the United States and running a criminal gang).
Initially he was trying to salvage the alien technology that crashed on Earth in order to give to the Nazis to help them in the upcoming war, but when the Laiderplacker arrived he immediately defected to their side, offering to tell them where to damage human society the most. After giving his information he was locked in their spaceship's hold where he discovered a defected Russian nuclear physicist who had just completed the world's first atomic bomb, which was then used to destroy the Laiderplaker. (AUDIO: Invaders from Mars)
Devine was probably middle aged as he remarked on one occasion that he was always trying to recapture his youth but it kept escaping. He wore a very ostentatious lilac suit. (AUDIO: Invaders from Mars)