Morse founded an early comics publishing company (1951-1956), variously called Key Publications, Aragon Magazines, Gillmor Magazines, Medal Comics, Publications Media, S. Publications, Stanmor Publications and Timor Publications.

During the 1950s boom in horror comics, Morse produced some of the most extreme, later claiming "You did what you had to do — what moved 'em off the racks... I don't know what the hell I published. I never knew. I never read the things. I never cared."

When the comics industry collapsed after the Fredric Wertham induced hysteria, Morse became a major publisher of men’s adventure magazines from the late 1950s to the mid-1970s. The Battle Cry comic was transformed into a men’s adventure magazine, published from 1955 to 1970 for more than 100 issues.

From 1969, Morse produced a short-lived range of titles reprinting his 1950s horror stories.