Jeff "Swampy" Marsh

Marsh at the 2009 San Diego Comic Con International

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.

In 1993, Marsh and Dan Povenmire came up with the idea for Phineas and Ferb. They went to several studios with the idea but the studios said no. In the 21st Century, Disney Channel told Povenmire they wanted to make Phineas and Ferb. Povenmire told Marsh and then Marsh came back to America to work with him on it. After Phineas and Ferb ended, Marsh and Povenmire created Milo Murphy's Law. They then made the movie Candace Against the Universe. Marsh is working with Povenmire on bringing back Phineas and Ferb.