Fragasso has co-written (with his wife Rossella Drudi) the scripts for many horror movies that were directed by the infamous Bruno Mattei, including Zombie 3, The Other Hell, Rats: Night of Terror, Hell of the Living Dead, Robowar, The True Story of the Nun of Monza, Emanuelle Escapes from Hell, and Shocking Dark, among others. Fragasso also co-directed a few of Mattei's films with him, including The Seven Magnificent Gladiators, Zombie 3, Scalps, White Apache, The Other Hell, Hell of the Living Dead and Rats: Night of Terror. (Fragasso even essayed a few minor acting roles in some of Mattei's films; i.e. he played a cameo role as a soldier in Zombi 3.)
In 1984, Fragasso directed his debut feature, Monster Dog, starring Alice Cooper as a rock-star werewolf.
In 1988, Fragasso and Mattei were called in by the producer of Zombie 3 (Franco Gaudenzi) to finish shooting the film when the director Lucio Fulci took ill and was forced to abandon the project halfway through. The two were whisked to the Philippines where filming had been under way, and finished the shooting in a few days, while Fulci was recuperating in a hospital in Rome. Fulci was furious that the producer had Mattei & Fragasso finish the film without him, and tried unsuccessfully to have his name removed from the credits.
After helping to complete Zombie 3, Fragasso was given funding by producer Gaudenzi to write and direct another low-budget zombie film, Zombie 4: After Death, in an attempt to recoup some of the money he had lost on Zombie 3. Fragasso's wife, Rossella Drudi, knocked out the script and he directed it on a shoestring budget, on the same sets they had used for Zombie 3.
After this Fragasso directed another horror film entitled Nightkiller, (aka "Don't Open The Door Part 3") that was never released in the United States and has since become a rare movie to locate.
With financial backing from famed Italian porn producer Joe D'Amato, Fragasso wrote and directed two infamous cult films on his own, La Casa 5: Beyond Darkness and Troll 2 - under the pseudonym Drake Floyd - (although Joe D'Amato claimed he co-directed some scenes in "Troll 2"). After this period of low-budget directing, Fragasso went on to direct bigger-budget films, such as the highly successful Palermo Milano Sola Andata (1994). He now works in Italian television.
In 2007, Michael Stephenson (who, as a child, played "Joshua Waites" in Fragasso's cult horror film Troll 2), along with George Hardy (who played Joshua's father Michael), flew to Rome to inform Fragasso about the large number of Troll 2 fans in America, and of the many people who show up at the Troll 2 screenings. Claudio (and his wife Rossella Drudi who wrote the film) flew to America, and have attended a few Troll 2 screenings. Claudio also took part in a documentary titled Best Worst Movie which was directed by Michael Stephenson. In addition, he and his wife toured the original locations of Troll 2 in Utah, with their fans.