Gary Carter, the slugging catcher known as Kid for the sheer joy he took in playing baseball, who entered the Hall of Fame as a Montreal Expo but who most famously helped propel the Mets to their dramatic 1986 World Series championship, died Thursday in West Palm Beach, Fla. He was 57.

The cause was brain cancer, which had been diagnosed last May. Carter had been treated with chemotherapy and radiation, but his daughter Kimmy Bloemers said in mid-January that new tumors had been discovered. She announced his death on her family journal at CaringBridge.org.

Carter played with intensity and flair, hitting 324 home runs and punctuating many of the ones he hit at Shea Stadium with arm-flailing curtain calls emblematic of the Mets’ swagger in the middle and late 1980s. In his 19 seasons in the major leagues, all but two of them with the Expos or the Mets, he was an 11-time All-Star and was twice named the most valuable player in the All-Star Game.

Carter’s exuberance complemented his prowess at the plate. Curly-haired and with a ready smile, he was loved by the fans, first in Montreal, then in New York.

“I am certainly happy that I don’t have to run for election against Gary Carter,” Pierre Elliott Trudeau, then prime minister of Canada, once remarked.

Carter excited Shea Stadium fans in his first game as a Met. After sliding into second with a double to left-center field in the 1985 season opener against the St. Louis Cardinals, he jumped up and pumped his right fist. In the 10th inning he hit a game-winning homer over the left-field fence, then pumped his arm again and again while he rounded the bases as the crowd roared. He was mobbed by his teammates at home plate, and when the fans chanted for a curtain call, he came out of the dugout waving both arms.

He was as exuberant behind the plate. When Carter tagged a runner out at home, he liked to punctuate the play by happily holding the ball aloft.

He may have led the 1986 Mets in hugging teammates.

Playing his first 11 seasons with the Expos, Carter became the face of the franchise, which sometimes struggled. But the Expos’ ownership chafed at his high salary and traded him to the Mets in December 1984 for four young players.

Some Expos were put off by Carter’s unabashed enthusiasm. They felt he was obsessed with his image and basked in his press coverage too eagerly. They called him Camera Carter.

“He had some problems among his teammates,” Andre Dawson, the Expos’ future Hall of Fame outfielder, told The New York Times after Carter was traded. They “felt he was more a glory hound than a team player,” Dawson said.

Carter said his reputation as a self-absorbed straight arrow burdened him.

“I carried a lot of baggage with me,” he told Jeff Pearlman for his book on the 1986 Mets, “The Bad Guys Won!” (2004). “I’d go to a new team and guys were saying they wondered how I was in the clubhouse, whether I had a big head or was a team player.”

The Mets teased Carter about his image, but they cared more about his power and his savvy behind the plate.

“We all disliked Gary when we played against him,” said Keith Hernandez, the star first baseman who became Carter’s Mets teammate. “He was just a little rah-rah varsity collegiate type, even though he didn’t go to college. But I respected him as a player. And when he came to New York, I appreciated him, too.”

Carter’s big opening day in 1985 was the prelude to a season in which he hit a career-high 32 home runs, setting the stage for the 1986 championship year.

In his five seasons with the Mets, the right-handed-hitting Carter, a brawny 6 feet 2 inches and 205 pounds or so, added considerable pop to a lineup that featured the left-handed-hitting Hernandez and Darryl Strawberry.

He had a powerful arm, he was sure-handed in blocking pitches in the dirt, and he was adept at handling pitchers, notably Dwight Gooden and Ron Darling.

“He’s the heart of the pitching staff,” Manager Davey Johnson once said. “We’d be lost without him.”

Carter hit 24 homers and drove in 105 runs as the Mets won 108 games in 1986. His 12th-inning single drove in the winning run in a 2-1 victory over the Houston Astros in Game 5 of the National League Championship Series. The Mets won that series in six games, then faced the Boston Red Sox in the World Series.

The Red Sox took the first two games. But Carter drove in three runs in Game 3, at Fenway Park, then hit two home runs over the left-field wall in Game 4, to help the Mets tie the series at 2-2.

After the Red Sox won Game 5, Carter touched off the most memorable single-inning rally in the Mets’ history.

The Red Sox were leading, 5-3, in the 10th inning of Game 6 at Shea and were one out from winning a World Series for the first time since 1918. The Mets had nobody on base.

Carter kept the Mets alive with a single off reliever Calvin Schiraldi, and a pair of singles brought him home. A wild pitch allowed the tying run to score. Then Mookie Wilson hit a grounder that went between the legs of Red Sox first baseman Bill Buckner, bringing Ray Knight home with the winning run.

The Mets won the World Series two nights later.

“Nothing will ever replace the moment when Jesse Orosco struck out Marty Barrett to end Game 7, and I was able to go out and jump in his arms,” Carter said when he was elected to the Hall of Fame. “That was my biggest thrill.”

Gary Edmund Carter was born on April 8, 1954, in Culver City, Calif., near Los Angeles. He was both an infielder and a star quarterback at Sunny Hills High School in Fullerton, Calif. He planned to play football at U.C.L.A. but pursued baseball instead when he was selected by the Expos in the third round of the 1972 draft.

The Expos switched Carter to catcher, and he made his debut for them in September 1974. Playing the outfield as well as catching in 1975, he was selected to the National League All-Star team and was the runner-up in the voting for National League rookie of the year. Carter became a full-time catcher in 1977.

The Expos reached the N.L. Championship Series in 1981, losing to the Los Angeles Dodgers. But by 1984 they were floundering, and they sent Carter to the Mets after the season.

After four solid years with the Mets, Carter was hampered by injuries. He played in only 50 games in 1989, when he hit .183, and was released after the season. He played for the Giants and the Dodgers, then ended his career back with the Expos in 1992.

In addition to his 324 home runs, Carter drove in 1,225 runs and had a career batting average of .262.His 298 home runs while in games as a catcher rank him No. 7 on the career list; Mike Piazza, the former Met, is No. 1, having hit 396 of his 427 homers while catching.

Carter won three consecutive Gold Glove awards, from 1980-82, with the Expos. He caught in 2,056 games, placing him No. 4 among major league catchers.

When Carter was elected to the Hall of Fame in 2003, the Hall’s management decided he would go in as an Expo rather than as a Met. Carter said he was happy with that but wondered aloud if he could be shown on the plaque wearing a “split” hat, one side representing the Expos, the other the Mets.

After his playing days, Carter was a roving minor league instructor for the Mets, a broadcaster for the Florida Marlins, a manager in the Mets’ minor league system and with the independent Long Island Ducks, and most recently the coach at Palm Beach Atlantic University.

Carter’s Palm Beach Atlantic coaching duties had been taken over by his assistants, but he visited his team on Feb. 2 when it opened its season in Jupiter, Fla., against Lynn University.

In addition to his daughter Kimmy Bloemers, the softball coach at Palm Beach Atlantic, Carter, who lived in Palm Beach Gardens, Fla., is survived by his wife, Sandy; his son, Douglas James, known as D. J.; another daughter, Christy Kearce; and three grandchildren.

When closing out his career in a second stint with the Expos (who left Montreal in 2005 and became the Washington Nationals), Carter, at 38, reflected on being known as the perennial Kid.

“Everybody calls me that,” he told The Times. “Even our rookie catcher, Tim Laker, calls me that. I got that nickname my first spring training camp with the Expos in 1974. Tim Foli, Ken Singleton and Mike Jorgensen started calling me Kid because I was trying to win every sprint. I was trying to hit every pitch out of the park.”