He spent the early part of his career at Fleischer Studios animating notable features such as Betty Boop, Popeye, Superman, and Gulliver's Travels, among other works.

[1] Born in Mechanicville, New York, he was the seventh of eight children of Patrick and Anna (Hammond) Holland, who were Irish immigrants from county Limerick.

[5] Sheehan joined the Fleischer Studio in 1933, where he worked animating various series of cartoon, such as Betty Boop, Popeye and Superman.

[6] Sheehan formed his own studio in 1944 that largely produced animated governmental and educational films, along with cartoons inspired by the work of Rube Goldberg.

I knew that I couldn’t [not] do this for a living, cause he still drew, like, that old Fleischer style in circles, and he was amazing and very inspiring, and I realized I couldn’t not do it.”[8] Sheehan received a lifetime achievement award from the International Animation Association (Midwest Chapter) and the Official Popeye Fan Club.