Originally intending to become an actor while at UCLA, Black was encouraged to try his hand at scriptwriting by a long-time friend, director Fred Dekker. At age 24, he wrote a screenplay which won him an agent and several meetings at studios, but instead of purchasing his script, the moguls wanted to give him assignments instead. Determined to see his original work produced, Black wrote "Lethal Weapon", a cop-buddy story about the partnering of a cop about to short his last fuse and a cop on the brink of retirement. Black was paid $250,000 for his script. When it was released in 1987, starring Mel Gibson and Danny Glover, "Lethal Weapon" grossed more than $100 million. Black wrote a script for "Lethal Weapon II" in which he had Gibson's character die. When Warner Brothers insisted Gibson live (for additional sequels), Black departed the project, but still shared screenplay credit. He was not involved with "Lethal Weapon III" or "Lethal Weapon IV," although both films were based on his characters.
In 1990, Black sold his screenplay for "The Last Boy Scout" for a then precedent-setting $1.75 million. The film was released the next year and was a disappointment at the box office, but did not harm Black's reputation. He received more than $1 million for his rewrites on "The Last Action Hero" (1993), and shared screenplay credit. Black again rocked the halls of the Writers Guild in July 1994 when he received $4 million for his spec script, "The Long Kiss Goodnight". Another action-adventure, "The Long Kiss Goodnight" was a departure for Black in that its central character is an amnesiac woman (Geena Davis) who learns she once worked as an assassin and discovers her secret history with the help of a run-down p.i. (Samuel L. Jackson). Although the hugely budgeted project did not make a major splash at the box office and reviewers were polarized, the film did have its share of admirers and saw its reputation improve over time.
After a lengthy hiatus in which he became better known for his high-profile Hollywood Halloween parties than for his screenplay output, Black finally returned--now both as writer and director--with a clever and highly satisfying tribute/send-up to the hard-boiled action genre with "Kiss Kiss Bang Bang" (2005), which also tweaked the mismatched-buddy film tradition which he himself had helped popularize in "Lethal Weapon." In the film a not-so-bright petty thief (Robert Downey, Jr.) is brought to Los Angeles for an unlikely audition and finds himself in the middle of a murder investigation, along with a gay but tough-as-nails detective (Val Kilmer) who has been training him for his upcoming role. Under Black's assured hand, the film winningly defied and sent up some well-worn genre conventions and cliches.
In addition to his prolific screenwriting--Black is much sought after for rewriting assignments--he has occasionally been able to play bit parts in movies, satisfying his original goal. He talked producer Joel Silver into giving him a small part in "Predator" (1987) as part of the "Lethal Weapon" deal, and has also appeared in his brother Terry Black's "Dead Heat" (1988), and "Robocop 3" (1993), as well as "As Good as It Gets" (1997).