Jeffrey Kent "Swampy" Marsh is an American animator, voice actor, writer, director, and producer. With Dan Povenmire, Marsh co-created the Disney Channel animated series Phineas and Ferb and Milo Murphy's Law, in both of which he voiced the character Major Francis Monogram. Marsh was born in Santa Monica, California, where he grew up with a heavily blended family dynamic. Marsh is known for his contributions to the television animation industry, 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.

Daniel Kingsley Povenmire is an American animator, voice actor, writer, director, and producer. With Jeff "Swampy" Marsh, Povenmire co-created the Disney Channel animated series Phineas and Ferb and Milo Murphy's Law, in both of which he voiced the character Dr. Heinz Doofenshmirtz. In October 2020, Povenmire announced a new series for Disney Channel titled Hamster & Gretel, which premiered in 2022.