Cartoonist Al Jaffee, then a fellow Timely editor, recalled in 2004, "Ernie was a very lively guy; very funny and fun to be with. He was an editor with Don Rico, and the two of them shared an office. Both men could write and draw... Ernie did humor work and Don edited certain titles. This was all post-World War II. One day, Stan called me in and said, 'I want you to edit the teenage books.' That may have been because Ernie left the company, because I do not recall Ernie editing anything but teenage and humor." Hart freelanced in the 1950s for that decade's Marvel predecessor, Atlas Comics, and also wrote for detective and true-crime magazines, occasionally being recruited to pose as a character on a photo-cover.