At age seventeen, William Stout won a full California State Scholarship to the Chouinard Art Institute. He began his professional illustrating career in 1968 with a cover for the first issue of the pulp magazine Coven 13. In 1971 he began to assist Russ Manning on the 'Tarzan of the Apes' daily newspaper comic strips, and in 1972, Stout joined Harvey Kurtzman and Will Elder on Playboy's 'Little Annie Fanny'. During the 1970s, he did a lot of underground comix work.
In 1977, William Stout became one of the first American contributors to Heavy Metal magazine. 'William Stout's Lost Worlds', the first of three trading card sets by Comic Images, was released in 1993. Stout became the first prehistoric wildlife painter to have a full color article devoted to his work. His work was an inspiration for Michael Crichton's book 'Jurassic Park'. In 1997 Stout collaborated with Moebius on a new 'Arzach' story for the 20th anniversary issue of Heavy Metal. Besides an illustrator, William Stout worked as a designer, producer and painter.