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. Jeff 'Swampy' Marsh(1960년생, Santa Monica, California, USA) 는 배우로, 대표작으로 고슴도치 영웅, Phineas and Ferb: Night of the Living Pharmacists, O.W.C.A. Files가 있으며, 그 외에도 피니와 퍼브, 마일로 머피의 법칙, 피니와 퍼브 무비: 캔디스, 우주에 맞서다, 피니와 퍼브 무비: 2차원을 넘어서, How Not to Draw, Agent P Under C, 피니와 퍼브: 스타워즈, Aaagh! It's the Mr. Hell Show!, 피니와 퍼브: 미션 마블, 아이 노우 댓 보이스, Phineas and Ferb: The Daze of Summer, Bounty Hamster 등 다양한 작품에 출연했다. 특히 2026년에는 Agent P Under C에도 참여해서 활동중이다. (오뜨랑에서 실시간으로 번역된 한글 프로필도 확인할 수 있어요) 2026년 Agent P Under C에서 Major Monogram (voice) 역을 맡았다. 2025년 Cartoonified! With Phineas and Ferb 제작에 참여했다. 2025년 고슴도치 영웅에서 Big Boss Croc / Exterminator (voice) 역을 맡았다.