Peanut (voiced by Thomas Allen) was hired by Harvey Birdman to be his legal clerk. He was inspired by the character Birdboy in the original Birdman and the Galaxy Trio series.In one episode,he was shown as a Tanning cream vendor/dealer.
Peanut is always a smooth talker, getting himself into trouble and out of trouble. He always dresses like Harvey in terms of the mask and costume, but other than that he wears a pink and green sweater vest. Where Harvey fails to catch uptakes, Peanut understands and gives more of his own. He constantly has, as Harvey says, "two different conversations" that frustrate Harvey. His age is never specified although he is believed to be at least 21. He also becomes more of a sidekick as episodes progress. When it comes to relationships, he considers himself a ladies' man often using pick-up lines. He also has an on-again off-again rivalry with Harvey's partner Avenger.
Unlike Birdman, Peanut's powers are not biological; his wings are mechanical, and his shield and energy beams come from "power bands" on his wrists, however in one episode, it has been hinted that Peanut does indeed become a superhero by going through "superty". Although not a power, he can speak Japanese, Spanish and French.