Jim "Catfish" Hunter, 53, one of the American League's most dominating pitchers of the early 1970s who played 15 seasons with the Athletics and Yankees, died Sept. 9 at home in Hertford, N.C.

A year ago, he learned he had amyotrophic lateral sclerosis, which is known popularly as Lou Gehrig's disease for the Hall of Fame Yankee first baseman who died of ALS in 1941 at the age of 37.

Mr. Hunter was a wily right-hander who was known for a crafty mix of pitches, a range of speeds and pinpoint control. He won the American League Cy Young Award in 1974, with a record of 25-12 for the Oakland Athletics. In five consecutive seasons, he won 20 or more games, and he helped pitch Oakland to three consecutive World Series championships in 1972, 1973 and 1974.

He pitched a perfect game against the Minnesota Twins in 1968. In 1987, he was elected to baseball's Hall of Fame.

In 1975, he left Oakland to sign with the Yankees for what then was a record $3.75 million, five-year deal; it followed a bidding war in which 23 of major league baseball's 24 clubs participated. That contract made Mr. Hunter the highest-paid player in baseball history, and it is generally considered to have helped open the door to a system that allows players relatively easy movement from one team to another in pursuit of multimillion dollar salaries.

After the 1974 season, Mr. Hunter had been declared a free agent by an arbitrator because Oakland had failed to make payments on an annuity that was part of his contract. At the time, baseball's reserve clause restricted player movement from team to team, and it was unprecedented to have a star of Mr. Hunter's magnitude available on the open market. Major league club executives flocked to his home town of Hertford, about 60 miles south of Norfolk, to recruit the pitcher, who was more interested in going out to hunt than in talking contracts.

"I was probably the first player who broke it open for other players to be paid what they're worth," Mr. Hunter said in 1987, after his election to the Hall of Fame.

He won 23 games in 1975, his first season with the Yankees, and he helped the Yankees reach the 1976 World Series, which they lost to Cincinnati in four games. But his athletic skills were fading. His shoulder hurt, he developed diabetes and his pitches lacked the bite they had once had.

For the 1977 season with the Yankees, he won nine and lost nine, but he also gave up 29 home runs in 143 innings. He was the losing pitcher in the second game of the 1977 World Series, giving up three home runs to the Los Angeles Dodgers in the first three innings. As he trudged off the field, fans at Yankee Stadium booed. "The sun don't shine on the same dog all the time," Mr. Hunter said after the game.

He retired after the 1979 season with a lifetime record of 224-166 and an earned-run average of 3.26. In his final season, his record was two wins and nine losses.

James Augustus Hunter was born in Hertford, a rural hamlet of 2,500, and he was one of eight children. A childhood accident almost cost him his baseball career before it started. A shotgun held by an older brother accidentally discharged near him, tearing off a little toe on his right foot. But he recovered, and by his senior year at Perquimans High School, he was being sought out by baseball scouts, having reached his full growth at six feet and 195 pounds.

He had a scholarship offer at East Carolina University, where he had thought about studying to become a game warden. But Charles O. Finley, owner of what then was the Kansas City Athletics, offered him a $50,000 signing bonus and in 1964 the young Mr. Hunter opted for a career in baseball.

It was Finley, a master showman, who gave him the nickname "Catfish," spreading the story that the young pitcher had acquired the name during childhood after running away from home and being discovered only after catching two catfish. In fact, Mr. Hunter was always known as "Jim" in his hometown. Only in baseball was he called "Catfish."

He was fiercely competitive on the field and a prankster who loved to have fun with teammates off the field. He grew a mustache and wore his hair long in the fashion of the late '60s and early '70s, but he retained his farm-boy values and spun stories with a country drawl.

During the 1965, 1966 and 1967 seasons, his record in Kansas City was unimpressive. Not until 1970 did he win more games than he lost. The Athletics moved from Kansas City to Oakland in 1968, the year that he pitched his perfect game against Minnesota.

Twenty-two years old at the time, he set down all 27 batters he faced, striking out 11 of them. The last batter of the game was Rich Reese of the Twins, who fouled off five straight pitches with a 3-2 count, then swung and missed at the game's final pitch. It was the first American League perfect game during the regular season since 1922 and the first by an American League pitcher since Don Larsen's perfect game for the Yankees in the 1956 World Series. The Athletics won the game 4-0, with Mr. Hunter driving in three runs.

After retiring from baseball, Mr. Hunter returned to his North Carolina home, where he hunted, fished and farmed.

Survivors include his wife of more than 30 years, Helen, who was his high school sweetheart; three children, Todd, Kim and Paul; and a grandson, Taylor.

CAPTION: A 1976 photo of Jim "Catfish" Hunter after he joined the Yankees.

CAPTION: Hunter bears down as a 19-year-old rookie for the Kansas City Athletics in 1965. In Oakland, he led the team to three consecutive World Series titles.