Gabriel first appeared in Haunt of Horror #2 (July 1974), and was created by Doug Moench and Billy Graham.

The character subsequently appears in Haunt of Horror #3–5 (September 1974 – January 1975), Monsters Unleashed #11 (April 1975), Fantastic Four #222–223 (September–October 1980), Marvel Comics Presents #106 (1992), Hellstorm: Prince of Lies #1–2 (April–May 1993), #5 (August 1993), #7–10 (October 1993 – January 1994), #12–14 (March–May 1994), #18 (September 1994), and #20–21 (November–December 1994).

Gabriel received an entry in The Official Handbook of the Marvel Universe: Horror #1 (2005).

Gabriel was a teacher at Columbia University who returned home one day to discover his pregnant wife Andrea murdered, although, puzzlingly, all the doors and windows were locked from the inside, and she appeared to be holding the murder weapon in her own hand. To cope with his grief, Gabriel joined a seminary and eventually took holy orders as a priest.^[1] Gabriel was possessed by a demon named Catherine, who compelled him to rip out his right eye, set fire to his holy sacraments, and burn his own house down. Gabriel grabbed a red hot metal cross and held it to his naked chest, searing the shape of the cross into his flesh and driving the demon from his body. Gabriel later met with the mysterious woman Desadia, and the two embarked on the career of professional exorcists.^[2] Desadia eventually became Gabriel's wife.^[1]

Gabriel often worked for ordinary people, but he also occasionally assisted superhumans as well, such as Red Wolf.^[3] Gabriel maintained an office on the 13th floor of New York City's Empire State Building.^[4]

Gabriel learned of Franklin Richards' possession by Nicholas Scratch and went to the Baxter Building to perform the exorcism. He forced Scratch to reveal himself, and accompanied Agatha Harkness, Franklin, and the Fantastic Four to New Salem, keeping Scratch subdued on the trip. The group was captured by Salem's Seven, whose power was augmented by Scratch. Gabriel and Agatha Harkness were able to forge the Fantastic Four's love for Franklin into a weapon, and drove Scratch out.^[5]

Gabriel left before the Fantastic Four could thank him, and continued to be plagued by demons. He retired for a time, and earned a meager living by writing occult "news" stories for the tabloid World Gossip Weekly and performing mock exorcisms for people interested in the occult. It was revealed that Desadia had been killed by the powers of evil. Gabriel helped Daimon Hellstrom foil the designs of a Daimon Hellstrom impostor performing human sacrifices in San Francisco. During this sequence of events, Gabriel was also able to overcome his crippling depression.^[6]

Gabriel later came into conflict with Daimon Hellstrom again, and he spiraled back into depression and alcoholism, and was on the verge of suicide.^[7] He was contacted by the Asura, the assassins of Heaven, and was convinced to work for them as a killer of demons.^[8] He later acquired a "Breathing Gun", a firearm capable of killing demons.^[9]

A final confrontation with Hellstrom left Gabriel irretrievably insane, only capable of babbling incoherently. Hellstrom left him in the care of the Gargoyle.^[10]

Gabriel is a trained exorcist, and if he failed to completely exorcise a demon, he was still able to suppress it, to minimize the harm it would cause its host. He had a cross-shaped scar burned into his chest, which he frequently used against the demons he fought. For a period of time he was also assisted during exorcisms by the spirit of his dead wife Andrea. While employed by the Asura, Gabriel owned a "Breathing Gun", a firearm that was able to harm or even kill demons.

Gabriel himself, either in spite of his abilities or because of them, was constantly plagued by demons attempting to possess him.

A female version of the character named Gabriella Rosetti appears in Helstrom on Hulu, played by Ariana Guerra.^[11] This version is a novitiate who is hired by Louise Hastings to eventually replace her as the head of Saint Teresa Center for Mental Health. Her faith is put to the test due to Daimon and Ana Helstrom's fight against Kthara who has inhabited their mother Victoria. Despite questioning Daimon's methods, she falls in love with him, but is impregnated by Daimon when the two of them are possessed by Kthara and Basar, respectively. Gabriella's pregnancy is rapid and she gives birth to Kthara in human form. Horrified by the recent events, Gabriella turns on her former allies and joins the Blood, presumably to end the Helstrom bloodline.

• Gabriel the Devil-Hunter at The Appendix to the Handbook of the Marvel Universe
• Gabriel the Devil-Hunter at Marvel of the Marvel Universe.