He has also worked as a writer, producer, voice director, story editor, and live-action director, among other things.
In the mid 1980's he started in animation screenwriting for Disney films such as The Fox and the Hound, The Black Cauldron, The Little Mermaid and Oliver & Company. He became a staff writier in the later 1980's and worked for many well-known Disney cartoons.
He was an episode writer and story editor of The New Adventures of Winnie the Pooh, with his personal writing style and subtle humor. He also co-created Talespin with Jymm Magon, which became the first new series for the newly formed Disney Afternoon block.
Around 1992, he left Disney and developed the Mighty Max animated series, based on the toy line. He developed the ABC Saturday moring cartoon called Cro. In 1994, he reunited with Jymn Magon for Superhuman Samurai Syber-Squad.
In 1994 he became a writer for the stop motion series Bump in the Night along with Ken Pontac and David Bleiman. Mark Zaslove was uncredited in films such as Space Jam, Quest for Camelot and The Iron Giant.
Later he worked on the animated gore and violence cartoon Happy Tree Friends. In the 2000's he worked on the children's show Lazytown as show writer and story consutant which was produced in Iceland.
He later become involved in the emerging entertainment industry in India and begining live-action writing and directing. He is a three-time Emmy award winner and a recipient of the Humanitas Prize.