The star of stage and screen played a villainous general in the first Lethal Weapon movie.
Former Lethal Weapons actor Michelle Ryan has died at the age of 88.
His step-daughter Denise Freed told The Hollywood Reporter that the stage and screen star died of heart failure at their Los Angeles home.
Mitchell played a villainous general in the first Lethal Weapon film, and was also a ruthless businessman on TV's Santa Barbara, with character roles in the soap opera Dark Shadows and the 1990s sitcom Dharma & Greg.
Sporting a rugged, granite-jawed mane and a sleek mane of hair, Michelle was instantly recognizable on TV and on the big screen.
His career spanned more than half a century, beginning with an uncredited role in the 1958 Robert Mitchum film Thunder Road.
His biggest roles included heroin smugglers in Lethal Weapon, a police officer in Magnum Force and Electra Glide in Blue, and murdered Las Vegas businessman Anthony Tonell in the nighttime TV soap opera Santa Barbara.
In the 1990s, he had a longtime role as Greg's wealthy, cynical and drunk father on Dharma and Greg.
Mitchell played Burke Devlin in the 1960s soap opera Dark Shadows for a series, but was fired due to alcoholism.
He acknowledged drinking issues in his 2021 autobiography Fall of a Sparrow.
"I am blessed to have been drunk for 30 years, I have managed to live the life of a working actor," he said.
"And I've lived a great deal of real life while I was at it.
"Sober for the next 30 years, I'm told I've come out of it all as a good and useful person."
Mitchell went on to play several TV shows and roles in films ranging from High Plains Drifter to Clint Eastwood to Halloween: The Curse of Michael Myers.
He also performed in theatre, including Broadway performances in Wait Till Dark, Medea and The Price.
Katherine Leigh Scott, who appeared with him in Dark Shadows, said in a Facebook post: "He was a great gift in my life. I cherish my warm memories of his beautiful soul. I am deeply saddened."