Harwell died at his home in Novi, Mich., the Tigers said. He had been diagnosed with cancer of the bile duct last year.
"All of Major League Baseball is in mourning tonight upon learning of the loss of a giant of our game, Ernie Harwell," Commissioner Bud Selig said in a statement. "This son of Georgia was the voice of the Detroit Tigers and one of the game's iconic announcers to fans across America, always representing the best of our national pastime to his generations of listeners."
Harwell spent 42 seasons in Detroit, describing the play of such Tigers stars as Al Kaline, Denny McLain, Jack Morris, Alan Trammell, Lou Whitaker and Kirk Gibson, and calling the action during the Tigers' 1968 and 1984 appearances in the World Series.
That long-running major league career started with a broadcast rarity: He was traded to the Dodgers from his job as a minor league announcer for a player. With the Tigers, he proved so popular the team had to rehire him in 1993 after trying to force his retirement in 1991.
"You know, nobody likes to be told he couldn't do the job," he recalled in 2002. "I don't think I got as excited as other people did.... A guy hires you, he's got a right to fire you."
But his stature with the city and the fans won out and he returned, retiring on his own terms after the 2002 season.
"I grew up listening to Ernie on warm summer nights with the radio under my pillow," Tigers television broadcaster Mario Impemba, who grew up in Detroit, told the Detroit Free Press in January. "Regardless of whoever sits in that chair from here on out, Ernie Harwell is the voice of the Detroit Tigers."
William Earnest Harwell was born Jan. 25, 1918, in Washington, Ga., and graduated from Emory University in 1940. He started writing for the Sporting News when he was only 16 and was sports director of Atlanta radio station WSB from 1940 to '42. Harwell served in the Marine Corps during World War II, including as a writer for Leatherneck magazine, and was on Wake Island in 1945 as a war correspondent.
He started broadcasting for the Atlanta Crackers of the Southern Assn. in 1943, returning to the job in 1946 after the war.
He came to the attention of Brooklyn Dodgers executive Branch Rickey, who sought Harwell's services in 1948 to fill in for an ailing Red Barber, who had to miss several weeks because of a bleeding ulcer.
There was only one problem: The Crackers' owner would let Harwell go only in exchange for a minor league catcher. So Harwell was traded to the big leagues.
In 1950, he moved to the New York Giants' booth, creating a vacancy with the Dodgers that was filled by Scully.
"Vinny took my place, which I consider my greatest contribution to baseball," Harwell told author Curt Smith in 2007.
At Dodger Stadium on Tuesday evening, Scully said, "All I did was sit in his chair, I'll put it that way."
"He was so gracious and kind," Scully said. "Probably the best word — he was gentle. He just cared for people and he loved baseball; I mean he loved it beyond just doing games. You can understand how the people in Detroit just loved him."
Harwell was broadcasting on television in 1951 when Bobby Thomson hit one of the most dramatic home runs in baseball history, rallying the Giants past the Dodgers in the final game of a three-game playoff for the National League pennant.
But few remember Harwell's call. Russ Hodges was on radio, and his description — "The Giants win the pennant! The Giants win the pennant!" — was taped and later released on an album, becoming part of baseball history. There's no record of the telecast.
"What did I get? Anonymity. What did Russ get? Immortality," Harwell jokingly told Smith for "The Vin Scully Story," published in 2009. "To this day only Mrs. Harwell and I know that I did maybe the most famous call of all time."