Born in Brooklyn, New York, Seeger began working as an animator for Fleischer Studios in the early 1940s. His credits included "A Kick in Time" for the Color Classics series and a sequence for the feature film "Mr. Bug Goes to Town".
During the later part of the 1940's, he worked as a screenwriter for a series of movies featuring well known Black performers, including the 1947 Cab Calloway musical Hi-De-Ho and two films featuring featuring Dusty Fletcher and Moms Mabley, "Killer Diller" and "Boarding House Blues".
He is best known for having produced the animated programs Milton the Monster (1965-66) and Batfink (1966-67). Another popular credit was Fearless Fly (1965), the adventures of a bumpkin fly who is physically helpless and practically blind without his trademark oversize rectangular glasses, but on putting them on he is invincible.