Lieber wrote and drew stories featuring superheroes, monsters and cowboys, plus an occasional love story for his brother's Atlas line, while teaching art classes on the side. He continued to work for Marvel during the Silver Age era of comic books. He scripted early installments of 'Thor' in Journey into Mystery, 'Iron Man' in Tales of Suspense and 'Ant-Man' in Tales to Astonish.
Lieber left Marvel in 1974 to become editor of the black-and-white comic book line published by Marvin Goodman's Atlas/Seaboard Comics. When the company folded, Lieber was an editor for Marvel UK, and wrote 'Captain Britain' and an occassional 'Spider-Man' story.
By 1978, Larry Lieber was the artist of the syndicated daily and Sunday strip starring Marvel's 'Incredible Hulk' (originally created by Stan Lee and Jack Kirby) through the Register and Tribune Syndicate. However, the comic was based more on the popular TV series 'The Incredible Hulk' (1978-1982) and ran parallel with its seasons. The character designs were even modelled after the TV actors. In 1979 Lieber passed the comic to Rich Buckler, who was succeeded later that year by Alan Kupperberg. In 1986, Lieber succeeded Fred Kida as the artist on the daily 'Spider-Man' comic, distributed by King Features and written by Stan Lee. He also drew the Sunday page between 1990 and 1995, but remains drawing the dailies up until at least 2015.