Clark suffered a "massive heart attack" on Wednesday morning, his rep says in a statement, after he entered St. John's Health Center in Santa Monica, Calif., for an outpatient procedure on Tuesday night.
"Attempts to resuscitate were unsuccessful. He is survived by his wife Kari and his three children, RAC, Duane and Cindy," the statement continues.
Clark, a diabetic, had suffered a stroke in 2004 but continued in recent years to appear on his New Year's Eve special from Times Square with Ryan Seacrest hosting.
"I am deeply saddened by the loss of my dear friend Dick Clark," Seacrest Tweeted. "He has truly been one of the greatest influences in my life. My thoughts and prayers are with his family."
The Mount Vernon, N.Y.-born Clark got his start in the mailroom of his father's radio station in upstate New York before working as a disc jockey at his college station and then in Philadelphia in the early 1950s.
When ABC picked up his dance show Bandstand, renaming it American Bandstand, the program became a sensation and featured the biggest the biggest names in the early days of rock 'n' roll – everyone from Little Richard to Chuck Berry.
Clark went on to produce and to host the $10,000 Pyramid and other game shows, as well as the American Music Awards, the Golden Globes and, starting in 1972, the New Year's countdown show Dick Clark's New Year's Rockin' Eve.
In December 2004, Clark suffered a major stroke that left him partially paralyzed with his speech impaired. After Regis Philbin filled in for him, Clark returned a year later for an emotional appearance on the show, addressing the audience in slurred speech.
"Last year I had a stroke," he said on the broadcast. "It left me in bad shape. I had to teach myself how to walk and talk again. It's been a long, hard fight. My speech is not perfect but I'm getting there."
He continued to appear on the show but later handed over hosting duties to Seacrest.
After his death, celebrity tributes poured in, including a poignant anecdote from Marie Osmond, a friend for 40 years.
"Last month, I wrote to him to send my love; and I added in my memory of first appearing with him on Bandstand in 1974 and what a life-changer he has always been for me," she tells PEOPLE. "He wrote back to congratulate me on my 21-year anniversary as a doll designer. Dick was always more interested in the accomplishments of others than he was in his own. Whenever Dick called me to be a part of anything he was producing, I would say 'yes' because I knew it would be done so well."