During the 1930s, Ernie Hart painted murals for the Works Progress Administration. In the following decade he joined Timely Comics, the future Marvel Comics, as part of its "animator" bullpen, separate from the superhero group that produced comics featuring the Human Torch, the Sub-Mariner and Captain America. Along with others including Vincent Fago, Jim Mooney, Mike Sekowsky, and future "Mad" magazine cartoonists Dave Berg and Al Jaffee, Hart worked on such movie tie-in and original funny-animal comics as "Terrytoons Comics", "Animated Funny Comic-Tunes" and "Mighty Mouse".