Pryor died shortly before 8 a.m. after being taken to a hospital from his home in the San Fernando Valley, said his business manager, Karen Finch. He had been ill for years with multiple sclerosis, a degenerative disease of the nervous system.
Music producer Quincy Jones described Pryor as a true pioneer of his art.
"He was the Charlie Parker of comedy, a master of telling the truth that influenced every comedian that came after him," Jones said in a statement. "The legacy that he leaves will forever be with us."
Pryor lived dangerously close to the edge, both on stage and off.
He was regarded early in his career as one of the most foul-mouthed comics in the business, but he gained a wide following for his universal and frequently personal routines.
But the risk taking that drove him to career success pushed his personal life over the edge – a serious addiction to alcohol and cocaine, reports CBS News correspondent Bill Whitaker.
Smoking cocaine in 1980, Pryor set himself on fire and almost died. He put it in a movie. It was only years later that he admitted he'd been trying to kill himself, reports Whitaker.
His audacious style influenced generations of stand-up artists, from Eddie Murphy and Chris Rock to Robin Williams and David Letterman, among others.
A series of hit comedies and concert films in the '70s and '80s helped make Pryor one of the highest paid stars in Hollywood, and he was one of the first black performers to have enough leverage to cut his own deals. In 1983, he signed a $40 million, five-year contract with Columbia Pictures.
His films included "Stir Crazy," "Silver Streak," "Which Way Is Up?" and "Richard Pryor Live on the Sunset Strip."
Throughout his career, Pryor focused on racial inequality, once joking as the host of the Academy Awards in 1977 that Harry Belafonte and Sidney Poitier were the only black members of the Academy.
Pryor once marveled "that I live in racist America and I'm uneducated, yet a lot of people love me and like what I do, and I can make a living from it. You can't do much better than that."
But he battled drug and alcohol addictions for years, most notably when he suffered severe burns over 50 percent of his body while freebasing at his home. An admitted "junkie" at the time, Pryor spent six weeks recovering from the burns and much longer from his addictions.
He battled multiple sclerosis throughout the '90s.
In his last movie, the 1991 bomb "Another You," Pryor's poor health was clearly evident. Pryor made a comeback attempt the following year, returning to standup comedy in clubs and on television while looking thin and frail, and with noticeable speech and movement difficulties.
In 1995, he played an embittered multiple sclerosis patient in an episode of the television series "Chicago Hope." The role earned him an Emmy nomination as best guest actor in a drama series.
"To be diagnosed was the hardest thing because I didn't know what they were talking about," he said. "And the doctor said `Don't worry, in three months you'll know.'
"So I went about my business and then, one day, it jumped me. I couldn't get up. ... Your muscles trick you; they did me."
While Pryor's material sounds modest when compared with some of today's raunchier comedians, it was startling material when first introduced. He never apologized for it.
Pryor was fired by one Las Vegas hotel for "obscenities" directed at the audience. In 1970, tired of compromising his act, he quit in the middle of another Vegas stage show with the words, "What the (blank) am I doing here?" The audience was left staring at an empty stage.
He didn't tone things down after he became famous. In his 1977 NBC television series "The Richard Pryor Show," he threatened to cancel his contract with the network. NBC's censors objected to a skit in which Pryor appeared naked save for a flesh-colored loincloth to suggest he was emasculated.
In his later years, Pryor mellowed considerably, and his film roles looked more like easy paychecks than artistic endeavors. His robust work gave way to torpid efforts like "Harlem Nights," "Brewster's Millions" and "Hear No Evil, See No Evil."
"I didn't think `Brewster's Millions' was good to begin with," Pryor once said. "I'm sorry, but they offered us the money. I was a pig, I got greedy."
"I had some great things and I had some bad things. The best and the worst," he said in 1995. "In other words, I had a life."
Recognition came in 1998 from an unlikely source: The John F. Kennedy Center for the Performing Arts in Washington gave Pryor the first Mark Twain Prize for humor. He said in a statement that he was proud that, "like Mark Twain, I have been able to use humor to lessen people's hatred."
Born in 1940 in Peoria, Ill., Pryor grew up in his grandmother's brothel. His first professional performance came at age 7, when he played drums at a night club.
Following high school and two years of Army service, he launched his performing career, honing his comedy in bars throughout the United States. By the mid-'60s, he was appearing in Las Vegas clubs and on the television shows of Ed Sullivan, Merv Griffin and Johnny Carson.
His first film role came with a small part in 1967's "The Busy Body." He made his starring debut as Diana Ross' piano man in 1972's "Lady Sings the Blues."
Pryor also wrote scripts for the television series "Sanford and Son," "The Flip Wilson Show" and two specials for Lily Tomlin. He collaborated with Mel Brooks on the script for the movie "Blazing Saddles."
Later in his career, Pryor used his films as therapy. "Jo Jo Dancer, Your Life is Calling," was an autobiographical account of a popular comedian re-examining his life while lying delirious in a hospital burn ward. Pryor directed, co-wrote, co-produced and starred in the film.
"I'm glad I did `Jo Jo,"' Pryor once said. "It helped me get rid of a lot of stuff."
Pryor also had legal problems over the years. In 1974, he was sentenced to three years' probation for failing to file federal income tax returns. In 1978, he allegedly fired shots and rammed his car into a vehicle occupied by two of his wife's friends.
Even in poor health, his comedy was vital. At a 1992 performance, he asked the room, "Is there a doctor in the audience?" All he got was nervous laughter. "No, I'm serious. I want to know if there's a doctor here."
A hand finally went up.
"Doctor," Pryor said, "I need to know one thing. What the (blank) is MS?"
Pryor was married six times. His children include sons Richard and Steven, and daughters Elizabeth, Rain and Renee.
Daughter Rain became an actress. In an interview in 2005, she told the Philadelphia Inquirer that her father always "put his life right out there for you to look at. I took that approach because I saw how well audiences respond to it. I try to make you laugh at life."