He wrote screenplays and stories for many popular animation shows including Batfink, The Beatles, Dungeons & Dragons and Spider-Man, providing the voice for the Green Goblin in the latter.

[2] He was awarded a bachelor's degree from Duke University in North Carolina, before serving in the United States Navy aboard the Lexington as a public information officer.

[3] Marks was hired by head of King Features TV, Al Brodax, to bring to television the comic strips of William Randolph Hearst, which the company handled.

[3] In between Marks had, with Friedman, continued to write songs for a Sherlock Holmes musical,[4] and was hired as a junior screenwriter on the American Scene Magazine for The Jackie Gleason Show.

In the late 1960s, Marks continued writing for various shows, including The Batman/Superman Hour and Aquaman, his first foray into superhero cartoons for DC.

[3] It was during this period that Marks wrote half of the hundred episodes to Hal Seeger's Batfink and worked on scripts for Max, the 2000-Year-Old Mouse.

[3] Marks was on the verge of settling in Los Angeles, when a meeting with Bob McAllister led to a job producing the weekly children's show Wonderama.

Although heavily involved in its creation, and by his own account creating the concept of the series protagonists being lost in a fantasy world through a fairground ride; he would not see the production through.

He also wrote the story for 1987 animated television film Yogi Bear and the Magical Flight of the Spruce Goose[3] to which he also provided the soundtrack and lyrics, and was a writer for a few episodes of Foofur.