He was born on February 17, 1920 in Minneapolis, Minnesota. Drafted into the army in 1940, he spent the war years working on the G.I. magazine, Stars and Stripes. After returning to civilian life in 1945 he began working for DC comics. After a stint on "Boy Commandos" he began to just pencil pages leaving the inks to others.
He drew many different features including Tommy Tomorrow and Gangbusters but slowly began gravitating towards the Superman line of books including Superboy and Superman's Pal Jimmy Olsen. He drew the daily newspaper strip Superman from the late fifties until it's demise in 1964.
Swan became the artist most associated with Superman over the years producing hundreds of covers and stories. With his frequent inker Murphy Anderson the pair's collaborative artwork came to be called Swanderson by the fans.
He retired in 1985 at the time DC comics put their characters through a major revamp.