[1] Born in Los Angeles, Marco started taking lessons in drama, singing and dancing at an early age.

His first known movie role was a small part in the 1944 film Sweet and Low-Down with Benny Goodman, Jo Stafford, and The Pied Pipers.

[1] In the early 1950s, The Amazing Criswell predicted on national television that Paul Marco would go far in the motion picture business.

He revived Kelton once more in the 2005 science fiction satire/tribute film The Naked Monster, which also featured actors from Creature from the Black Lagoon, The Thing from Another World, The War of the Worlds, Beyond the Time Barrier, and The Indestructible Man, all reprising the roles they had played in the cited earlier films.

He completed the first, entitled Kelton's Dark Corner (by Vasily Shumov), and was planning to shoot several scenes for the second before his death.