[2] Shannon already appeared in a small role in Vino, whisky e acqua salata (1962), but started his film career starring in Roberto Mauri's Le porno killers (alongside Carmen Russo) and in Joe D'Amato's Caribbean films Porno Holocaust, Erotic Nights of the Living Dead, Hard Sensation, and Sesso nero, all shot in the second half of 1979 and released in 1980 and 1981.

[5] Shannon continued to star in many films by Joe D'Amato, but also of Mario Bianchi, Antonio D'Agostino, Sergio Bergonzelli and Claudio Bernabei, until 1983.

[6] He had scenes with many notable Italian pornographic actresses, among them Lucia Ramirez, Annj Goren, Marina Frajese, and Moana Pozzi.

[6] From 1984 to 1988, Shannon was correspondent for "International Travel Dixie Bird",[5] after which he returned to Italy, working in tourism until 2004.

[8] For the blu-ray Erotic Nights of the Living Dead released by Code Red on June 15, 2018, in the United States, Mark Shannon gave a 20-minute interview in which he talked about his experiences as hardcore pornographic actor and how they came to affect his life both during his active time and beyond.