Malcolm Long is the psychiatrist who attempts to treat Walter Kovacs while he is imprisoned. He appears prominently in the sixth chapter of Watchmen.
Long is married to a woman named Gloria Long. He served as a criminal psychiatrist at Sing Sing prison. One of his patients was Walter Kovacs, who'd been arrested by New York City Police after he'd attacked several SWAT team members at the former tenement of Edgar Jacobi who'd previously led a double life as Moloch, an underground criminal kingpin.
Kovacs relates the story of his transformation into his vigilante personna, Rorschach, to Long during a lengthy conversation. Kovacs tells Long that his psychological breakdown came as a result of his investigation of the kidnapping of Blair Roche, a six-year-old girl, whose captor, Gerald Anthony Grice, believed was an heir to a fortune from the Roche Chemical Company. In fact, young Blair's father was simply a bus driver and not wealthy at all. Kovacs' investigation reveals that Grice had butchered the child and fed her remains to his two German Shepards.
Long himself becomes affected by Kovacs; the intensity of Kovacs story causes Long to become slightly obsessed with the case. It has a damaging effect on his marriage; in one instance, some guests whom his wife has invited to dinner, start to tease Long about Kovacs. Unamused, Long tells them in detail about Grice's murder of Roche and how he disposed of the girl's body. After their guests have left, Long's wife berates him and accuses him of focusing more attention on his work than her.
Later Long and his wife have separated and are attempting to make amends when Malcolm witnesses Joey annd Aline fighting; they both are killed when Adrian Veidt's monstrous alien creature is teleported nearby.
The film version of Malcolm Long is not as cheerful and as optimistic as he is in the graphic novel and is only seen in a few scenes; when interviewing Rorschach (after which he tells the guard that he cannot help him), during the prison riot when he hides in a storage room and meets Rorschach again, and near the end of the movie when he is killed by the explosion. His wife and personal life are neither seen nor mentioned.
A movie prop with Rorschach's case file mentions the name Dr. Terrence Roberts.