Robert Creel Davis was born in Tallahassee, Florida. Known in his youth as Bobby, he changed his name to Brad in 1973 because there was already a Bobby Davis listed with Actors Equity. In Davis's earliest years his family enjoyed a relatively affluent life. His father, Eugene Davis, was a successful dentist. Davis moved with his family to Titusville, Florida.
Acting was young Brad Davis's lifelong ambition. After winning a music talent contest at the age of seventeen, he worked at Theatre Atlanta. Later he attended the American Academy of Dramatic Arts and studied acting at the American Place Theater in New York.
After appearing in several off-Broadway productions, he won a regular part on a television soap opera, How to Survive a Marriage, in 1974. He came to greater public attention in 1976 with a major role in the television movie Sybil, directed by Daniel Petrie; and the following year he appeared in the highly-acclaimed mini-series Roots, directed by Marvin J. Chomsky and John Erman.
Davis's cinematic breakthrough came in 1978 when he starred as imprisoned drug-smuggler Billy Hayes in Alan Parker's Midnight Express. His performance earned him a Golden Globe award as best new actor, but other important roles were not immediately forthcoming. His next film, Rob Cohen's A Small Circle of Friends (1980), was not a success, and his role in Hugh Hudson's 1981 hit Chariots of Fire was a relatively minor one.
In 1983 Davis took a professional risk by accepting the title role as a gay sailor in Querelle, Rainer Werner Fassbinder's screen adaptation of a novel by Jean Genet. Associates in the entertainment industry warned Davis that taking this part, especially after performances in other gay-themed theatrical works such as Larry Kramer's Sissies' Scrapbook (1973) and Joe Orton's Entertaining Mr. Sloane (1981), would be detrimental to his career. Nevertheless, Davis chose to work with Fassbinder on what would turn out to be the director's last film. Unfortunately, Querelle was a commercial failure and generally not well-received by critics.
In 1985 Davis won critical acclaim for his portrayal of the lover of a man dying of AIDS in Larry Kramer's play The Normal Heart. Still, his film career foundered. The only other movie in which he starred was Percy Adlon's 1989 comedy Rosalie Goes Shopping.
Davis continued to find work in foreign films and on television, including the title role in Marvin J. Chomsky's 1985 mini-series, Robert Kennedy & His Times, but he never realized his full potential as a film actor. Homophobia in Hollywood is one likely cause of this, but the problem was exacerbated by Davis's reputation for erratic behavior - mostly off the set - caused by alcohol and drug use.
Davis, a longtime alcohol-abuser who had begun using cocaine while filming Midnight Express, joined Alcoholics Anonymous in 1981 and eventually became sober; but during the period of his substance abuse, he was involved in a number of incidents of unruly conduct, some of which led to arrests.
In 1985 Davis learned that he was HIV-positive. Fearing that he would be unemployable if word of his condition became known, he shared the information only with his wife, Susan Bluestein Davis, whom he had married in 1976, and a few close friends. He received medical treatment from a doctor who came to his home; and later when he required hospital stays, he checked in late at night and used his given name, Robert Davis.
The treatments were unsuccessful, and, according to Robert Pela, Davis ended his life by committing an assisted suicide at his home in Studio City, California.
After his death newspaper reports described him as "the first heterosexual actor to die of AIDS," but his bisexuality was well known to people in the entertainment industry.
Bluestein Davis acknowledged that in his early years in New York, her late husband had "hustled" in Times Square and had lived with a transvestite, but she insisted that he was heterosexual. However, the description of Davis as heterosexual is contradicted by other sources.
Davis's friend gay writer Rodger McFarlane said that Davis "never [said] he wasn't gay when someone asked." The late actor Timothy Patrick Murphy spoke of having had an affair with Davis in the mid-1980s. In an interview that appears in Boze Hadleigh's book Hollywood Gays, Davis himself acknowledged having had sex with men and, when asked if he considered himself bisexual, he replied "didn't someone once say that everyone's bisexual, deep down?"