Jeff 'Swampy' Marsh
Acting
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
2025Spiked
(voice)
2020Phineas and Ferb the Movie: Candace Against the Universe
Major Monogram (voice)
2015TV's Funniest Animated Stars: A Paley Center for Media Special
Self
2015O.W.C.A. Files
Major Monogram / Additional Voices (voice)
2015Phineas and Ferb: Last Day of Summer
Major Monogram (voice)
2014Phineas and Ferb: Night of the Living Pharmacists
Major Francis Monogram (voice)
2014Phineas and Ferb: Star Wars
Major Hologram / Imperial Officer Jeff / Additional Voices
2014I Know That Voice
Self
2014Phineas and Ferb Save Summer
Major Francis Monogram / Additional Voices (voice)
2013Phineas and Ferb: The Perry Files - Animal Agents
Major Monogram (voice)
2013Phineas and Ferb: Mission Marvel
Francis Major Monogram / Gordon Gutsofanemu / Additional Voices
2012Phineas and Ferb: The Daze of Summer
2011Phineas and Ferb The Movie: Across the 2nd Dimension
Major Francis Monogram / Monogram-2 (voice)
2010Phineas and Ferb: Summer Belongs to You!
Major Francis Monogram / Additional Voices (voice)
2009Phineas and Ferb Christmas Vacation!
Major Monogram (voice)
Untitled Phineas and Ferb Movie
Major Francis Monogram (voice)