His father died when Kneitel was still in high school, and he needed work to provide support for his mother and sister.
[1] He was able to attend an annex of Commerce HS and work after school and Saturdays for Bray Studios, coloring drawings for Colonel Heeza Liar cartoons.
In 1928 he worked for six months at Loucks and Norling on industrial films and the Mutt and Jeff series.
Kneitel wrote several Superman episodes with Isadore (Izzy) Sparber, and directed one short, The Mechanical Monsters (1941).
In January 1942, the Fleischer brothers were forced to resign from the studio they had created; they had borrowed money from Paramount between 1938 and 1941 to finance their expanded Miami facilities and two feature films.
Due to the usage of limited animation, the quality of these films is inferior to those produced by the Fleischer and Famous Studios.
[4] His son, Tom Fleischer-Kneitel, an avid amateur radio operator (License K2AES), was the founding editor of Popular Communications magazine, and died on August 22, 2008, at the age of 75.
Seymour's youngest son, Kenneth, a major collector of vintage material, established and ran the store 'Fandango' in New York City.