Jeff 'Swampy' Marsh was born on December 9, 1960 in Santa Monica, California, USA. He is a writer and actor, known for Phineas and Ferb (2007), Phineas and Ferb the Movie: Across the 2nd Dimension (2011) and Milo Murphy's Law (2016). He has been married to Birgitte since December 17, 2006. They have two children.