

Biography
Jeff "Swampy" Marsh (born December 9, 1960) is an American animator, writer, director, producer, and voice actor associated with several animated television series, most notably as an executive producer and the voice of Major Monogram for Disney's animated series Phineas and Ferb and Milo Murphy's Law, both of which he co-created with Dan Povenmire. 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.
Known For
Spiked (2025)Age: 65as (voice)
How NOT to Draw (2022)Age: 62as Major Monogram (voice)
Phineas and Ferb the Movie: Candace Against the Universe (2020)Age: 60as Major Monogram (voice)
Milo Murphy's Law (2016)Age: 56as Additional Voices (voice)
O.W.C.A. Files (2015)Age: 55as Major Monogram / Additional Voices (voice)
Phineas and Ferb: Last Day of Summer (2015)Age: 55as Major Monogram (voice)
Phineas and Ferb: Night of the Living Pharmacists (2014)Age: 54as Major Francis Monogram (voice)
Phineas and Ferb: Star Wars (2014)Age: 54as Major Hologram / Imperial Officer Jeff / Additional Voices
Phineas and Ferb Save Summer (2014)Age: 54as Major Francis Monogram / Additional Voices (voice)
Phineas and Ferb: The Perry Files - Animal Agents (2013)Age: 53as Major Monogram (voice)






