Before World War II, Mr. Morton worked on Felix the Cat, Betty Boop, Popeye and other cartoon characters. He wrote about 25 of the early animated "Superman" cartoons, in which he initially described the comic book superhero as "faster than a streak of lightning, more powerful than the pounding surf, mightier than a roaring hurricane, this amazing stranger from the Planet Krypton, Superman." But he soon reworked the introduction to the now-familiar: "Faster than a speeding bullet, more powerful than a locomotive, able to leap tall buildings in a single bound..."
Mr. Morton left Fleischer in the early 1940s and became publisher of Florida newspapers and trade papers. He was also known as a sculptor. His eight-foot bronze sculpture of Adm. Richard E. Byrd, the Antarctic explorer, was installed at the entrance to the courthouse in Byrd's home town, Winchester, Va.