Jeff “Swampy” Marsh (born December 9, 1960) is an American television director, writer, producer, storyboard artist, and actor associated with several animated television series.

Marsh was born in Santa Monica, California, where he grew up with a heavily blended family dynamic. Marsh has been and continues to be a driving force behind several animation projects, working for over six seasons on the animated television series The Simpsons. Marsh continued to work on other animated television series, including King of the Hill and Rocko’s Modern Life, before moving to England in 1996.

Co-creator, director, writter, and he portrays the voice of Major Francis Monogram, Perry the Platypus’s commander in Phineas and Ferb (Hit Disney Channel Original Serie). In 1996, he won an EMA award for Children’s Animated Television Program: Rocko's Modern Life, for episode “Zanzibar.”