Nicknamed "Pudge" as a youngster, Fisk grew to be 6-foot-2 and 220 pounds and he was one of the best catchers in baseball for more than twenty years.

After brief stints with the AL's Boston Red Sox in 1969 and 1971, Fisk became the team's starting catcher in 1972, when he led the league in triples with 9, batted .293, and was named rookie of the year.

He missed much of the 1974 season and the early part of the 1975 season with an injury, but he came back to help lead the Red Sox to a pennant, batting .331 with 10 home runs and 52 RBI in just 79 games. His winning home run in the 12th inning of Game 6 in the World Series has been often replayed, because Fisk watched the ball and used body English to try to keep it inside the foul pole. However, Boston lost to the Cincinnati Reds in the seventh game.

In 2,499 major league games, Fisk had 2,356 hits, including 421 doubles, 47 triples, and 376 home runs. He scored 1,276 runs and drove in 1,330. He hit 350 of his home runs as a catcher, an AL record, and he holds AL catching records for most years, 24; most games, 2,201; most putouts, 11,612, and most chances accepted, 12,676.

At the time of his retirement in 1993, he held the record for most home-runs all-time by a catcher  with 351. Fisk was voted to the All-Star team 11 times. Fisk was known as a fierce competitor, a superb handler of pitchers and a natural on-field leader. He was elected to the Baseball Hall of Fame in 2000.