When George Carlin was in his teens his mother found a list of dirty words in his wallet. Young George explained how he liked writing down colorful curses he'd hear in his neighborhood near New York City's Harlem. That night, "I heard her talking to my uncle," Carlin recalled in a 2004 National Public Radio interview, "saying, 'I think he may need a psychiatrist.'"

Instead he got a microphone and spent more than half a century making people laugh. Before his June 22 death from heart failure at age 71—he'd suffered at least two heart attacks in previous years—Carlin cut more than 20 comedy albums, won four Grammys, taped 14 HBO specials and wrote three bestsellers, mostly based on his vitriolic view of the human race. But his signature moment was "Seven Words You Can Never Say on Television," a routine deemed indecent by the U.S. Supreme Court in 1978. "Before him, comics aspired to put on nice suits and perform in Las Vegas," says Jay Leno. "George rebelled against that life."

Raised by his Irish-Catholic mother, Mary, a secretary (his father died when George was 8), Carlin dropped out of high school and served in the Air Force before working his way up through comedy clubs (he hosted the first Saturday Night Live in 1975). Oddly endearing as Mr. Conductor on the Thomas the Tank Engine children's show in the '90s, he entered rehab in 2004 to come down off what he called "a 54-year buzz" from booze and pills. "This was the best 10 years of my life," says his companion, Sally Wade, a TV writer (Carlin's wife, Brenda, died in 1997; they had a daughter, Kelly, 45). "It's quite a shock right now."

Not that Carlin ever minded surprising a crowd. For his tombstone, he told Playboy in 2005, "I'm thinking something along the lines of 'Geez, he was just here a minute ago.'"