Born in New York City, Williams decided to go into acting when he accidentally walked onto a New York stage, and made his debut on Broadway (in The Long Dream, 1960). He had numerous roles there, and was nominated for a Tony award for his role in Slow Dance on the Killing Ground. He was spotted in that show by Bill Cosby, who recommended Williams as an actor to TV producer Aaron Spelling, who was working on a new show. Spelling brought him in for a bit part as a getaway driver. “They went in, they rob the store, you heard a pistol shot and they ran [to] the car,” Spelling remembered later. “Then he drove off and smashed right into a telephone pole. I thought everybody was killed. We all rushed over. I said, ‘Clarence, Clarence, what happened?’ He said, ‘I’ve never driven before.’ I said, ‘Why didn’t you tell me that?’ He said, ‘Because I wanted the job.’ I hired him that night for ‘Mod Squad’.”
The “counterculture” Mod Squad police drama (1968–1973) was a breakout show: Williams played detective Lincoln “Linc” Hayes opposite two other relatively unknown co-stars, Michael Cole as Peter Cochran, and Peggy Lipton as Julie Barnes. Williams was the epitome of cool with his perfect afro and dark glasses. In one episode, Linc was supposed to give Barnes a friendly kiss on the cheek. The network went crazy: “You can’t do that!” Spelling remembers network brass telling him. “You can’t have a black man kissing a white girl!” He fought for the scene and ABC relented — “but they warned me I’d receive thousands of complaint letters. I didn’t get one.” Perhaps because Star Trek beat them to the punch with a much more intimate interracial kiss.
After the show ended, Williams went on to other roles, including guest spots on Hill Street Blues, Miami Vice, Twin Peaks, Star Trek: Deep Space Nine, and Law and Order. In longer formats he played Prince’s father in Purple Rain, and a recurring role as “Philby” in the Mystery Woman series of TV movies (2005–2007). Williams’ last role was in 2015. He died June 4 from colon cancer, at 81.