Mr. Williamson was a galvanic presence in dozens of stage and film roles and drew favorable comparisons with Laurence Olivier and Charles Laughton.
Author Samuel Beckett pronounced him “touched by genius.” The British playwright John Osborne, who made Mr. Williamson a marquee name in the 1964 drama “Inadmissible Evidence,” considered him “the greatest actor since Marlon Brando.”
With his nasally twang, receding ginger hair, despairing eyes and hangdog face, Mr. Williamson had little of the young Brando’s beauty and raw physical power. He compensated with a demeanor that conveyed cunning, an explosive temperament and a general aura of sweaty self-loathing.
These traits were on display in Mike Nichols’s 1974 staging of Anton Chekhov’s “Uncle Vanya,” for which Mr. Williamson in the title role won the Tony Award for best actor.
Onscreen, Mr. Williamson excelled as a cocaine-addicted Sherlock Holmes in “The Seven-Per-Cent Solution” (1976), a ruthless Afrikaaner policeman in apartheid South Africa in “The Wilby Conspiracy” (1975) and the wizard Merlin in director John Boorman’s violent retelling of the King Arthur legend in “Excalibur” (1981).
Willfully or not, Mr. Williamson seemed determined to torpedo his reputation through heavy drinking and erratic, often abusive behavior.
Coming to the defense of a stage director, Mr. Williamson threw beer on the notoriously cruel theater impresario David Merrick and then punched him. Other stories, perhaps embellishing the incident, have Mr. Williamson tossing Merrick in the trash. Mr. Williamson later quipped, “The funny thing was that nobody in his entourage tried to attack me or help him.”
Mr. Williamson’s notoriety for turbulent antics resurfaced while he starred as King Henry VIII of England in the 1976 Broadway musical “Rex.” It ran 48 performances and was best remembered for Mr. Williamson slapping another actor for talking when Mr. Williamson was taking his bow during curtain call.
The two incidents might have been written off had Mr. Williamson not whacked the actor Evan Handler with a sword when they were starring on Broadway in Paul Rudnick’s 1991 comedy “I Hate Hamlet.” Mr. Williamson played the ghost of John Barrymore, the highly gifted, randy and alcoholic actor of the early 20th century.
During a sword fight with Handler, Mr. Williamson appeared to improvise lines: “Put some life into it! Use your head! Give it more life!” Handler walked offstage, and Mr. Williamson broke the awkward silence by turning to the audience and asking, “Well, should I sing?”