Bell played for the Pirates from 1950 through 1952. On June 4, 1951, he hit for the cycle against the Philadelphia Phillies. In 2004, his grandson David hit for the cycle; Gus Bell and David Bell are the only grandfather-grandson duo in major league history to hit for the cycle.

With Cincinnati from 1953 through 1961, Bell was a four-time National League All-Star selection (1953–54, 1956–57). He enjoyed his best seasons in 1953, when he hit .300 with 30 home runs and 105 RBI, and 1955, batting .308 with 27 home runs and 104 RBI. Four times, he recorded more than 100 RBI in a season and hit 103 home runs from 1953 to 1956.

Bell hit home runs in three consecutive at-bats on May 29, 1956. During the 1956 season, Bell, Ted Kluszewski and Bob Thurman became the second trio of teammates each to have three-home run games in the same season. The feat had been accomplished by the Brooklyn Dodgers in 1950 (Duke Snider, Roy Campanella and Tommy Brown) and subsequently was equally by the Cleveland Indians in 1987 (Cory Snyder, Joe Carter and Brook Jacoby).

In 1957, Bell and six of his teammates – Ed Bailey, Johnny Temple, Roy McMillan, Don Hoak, Wally Post and Frank Robinson — were voted to the National League All-Star starting lineup, the result of a ballot stuffing campaign by Cincinnati fans. Bell remained on the team as a reserve, but Post was taken off altogether due to injury. Bell and Post were replaced as starters by Hank Aaron and Willie Mays. Bell entered the game as a pinch hitter for Robinson in the seventh and drove in both Mays and Bailey with a double against Early Wynn.

Bell’s last season as a regular outfielder was 1960, when he started 122 of the Reds’ 154 games. In 1961, his final year with Cincinnati, he was a part-time player (starting 54 games) on the Reds’ first pennant-winning team in 21 years. In the 1961 World Series, Bell was called on to pinch hit in Games 3, 4 and 5 and went hitless in three at bats. One day after the conclusion of the Fall Classic, won by the New York Yankees four games to one, Bell was the eighth overall selection in the primary phase of the National League expansion draft by the New York Mets.

Bell started the 1962 season with the Mets, and on April 11, 1962, he was the starting right fielder in the Mets’ inaugural game. He became the first base runner in Met history after hitting a single in the second inning of an 11–4 loss to the St. Louis Cardinals. But he collected only 15 hits in 101 at bats (.149) in 30 games with the expansion club.

On May 21, 1962, Bell was sent to Milwaukee to complete a November 1961 transaction in which the Mets acquired veteran slugger Frank Thomas. He batted .285 in 79 games (with 53 games started as an outfielder) to raise his 1962 season average to .241. But he had only six more MLB at bats as a Brave in 1963–64 until he was released on May 12, 1964, during the roster cutdown then in effect in the major leagues.

Bell was inducted into the Cincinnati Reds Hall of Fame in 1964. After his playing career, he worked for an auto dealership, ran a temporary employment agency, and was a scout for the Cleveland Indians and Texas Rangers. Bell died in May 1995, at Bethesda North Hospital near Cincinnati; he had recently had a heart attack. He was survived by seven children and 36 grandchildren.

A native of Louisville, Kentucky, and graduate of Bishop Benedict Joseph Flaget High School, Bell was the oldest member of a rare three-generation major league family. His son, Buddy, has been a third baseman, coach, manager and front-office executive in the majors, and his grandsons, David and Mike, are both former infielders who have remained in baseball after their playing careers as coaches, managers or player development officials. Gus Bell wore uniform #25 during his nine years with the Cincinnati Reds (known as the “Redlegs” from 1953–58); Buddy Bell wore 25 in tribute to his father during much of his playing and managing career, including his tenure with the Reds. David, named manager of the Reds in 2019, carried on the tradition when he took Cincinnati uniform #25 as well.