Gregory Rodman Irons was born in Philadelphia, Pennsylvania in 1947. He was self-taught as an artist, being influenced by early MAD pocket books. He moved to San Francisco in 1967, where he started out doing a series of posters for the Fillmore Auditorium. Through Bill Graham Productions, he has done poster art for bands such as Moby Grape, Jefferson Airplane, CSNY and Santana. He then moved to London, England where he stayed until 1969, working on the classic Beatles animation 'Yellow Submarine'. Back in San Francisco he continued making posters, as well as designing record covers and drawing comics, such as 'Heavy', published by the Print Mint in 1969. This was followed by 'Light'. Irons also did contributions to 'Yellow Dog'.
Greg Irons was one of the contributors to Slow Death Comics, Dr. Wirtham's Comix & Stories and Skull Comix in the early 1970s, as a part of the American underground comix scene. In San Fancisco, Irons teamed up with writer Tom Veitch, with whom he created characters such as Jumpin' Jack Flesh, Our Mutant Brothers and Vince Shazam.
By the mid-1970s, Irons started doing more book illustrations, among others for Troubadour Press, Sunset Books and Bellerophon Books. He also began working as a tattoo artist. Greg Irons was killed on 14 November 1984 by a city bus in Bangkok, shortly after having received a magic tattoo from a Buddhist monk in Chiang Mai.