[3] After his time in the Navy, Prentice briefly attended the Art Institute of Pittsburgh, and then moved to New York City, where he worked in a variety of illustration and comic-book jobs.

Among the most notable of his comic-book illustration work for DC Comics were for titles such as House of Secrets, Tales of the Unexpected, Gang Busters, and the first issue of Showcase.

Showcase's inaugural issue introduced the character Fireman Farrell, a co-creation of Prentice and writer Arnold Drake's.

[8] On September 6, 1956, Flash Gordon creator Alex Raymond was killed in a car crash, leaving his current comic strip, Rip Kirby, without an illustrator.

[11] Prentice received the National Cartoonists Society Story Comic Strip Award for Rip Kirby in 1966, 1967, and 1986.