A left-handed batter and thrower, Tanner signed his first professional baseball contract with the Boston Braves. He played for eight seasons (1955–1962) for four teams: the Milwaukee Braves, Chicago Cubs, Cleveland Indians and Los Angeles Angels. In 396 games played, Tanner batted .261 with 21 home runs. While with the Braves, Tanner hit a home run off the first pitch in his first career at-bat on April 12, 1955. He is the only Braves player to hit a home run in his first at-bat in Milwaukee.

Tanner is best known as a manager, having managed four teams from 1970 to 1988. His overall managerial record was 1,352–1,381 in 17 full seasons and parts of two others.
Tanner spent his entire Minor League managing career in the Angels' system. In 1963, Tanner began his managerial career with the single-A Quad Cities Angels in the Midwest League, and spent the next seven seasons climbing the Angels' organizational ladder, including managing the El Paso Sun Kings (1965-1966 and 1968), and Seattle Angels (1967). He won the Texas League title with El Paso in 1968. In 1970 he led the AAA Hawaii Islanders to 98 wins in 146 games and a berth in the Pacific Coast League (PCL) championship series.
Both Tanner and Roland Hemond joined the Chicago White Sox from the Angels on September 4, 1970, when general manager Stu Holcomb hired them as manager and director of player personnel respectively. Tanner, who signed a two-year contract, replaced Don Gutteridge who had been dismissed two days prior. Due to the Islanders qualifying for the PCL championship series, he was unable to make his White Sox managerial debut until September 15, requiring Bill Adair to serve in the interim. Tanner did not retain Adair for his staff after the season, but he named Al Monchak and Joe Lonnett as his first- and third-base coaches respectively on October 2, 1970. All three went on to serve in similar capacities together with the White Sox (1971–75), Oakland Athletics (1976) and Pittsburgh Pirates (1977–84), with Monchak continuing as Tanner's first-base coach with the Atlanta Braves from 1986 to 1988.

With the White Sox, Tanner managed such star players as Wilbur Wood, Carlos May, Bill Melton, and the temperamental Dick Allen, who like Tanner was a native of Lawrence County, Pennsylvania by way of Wampum. His most successful season with the Sox came in 1972, when he managed them to a close second-place finish behind the eventual World Series champion Oakland Athletics in the American League (AL) Western Division. The pitching staff was led by 24-game winner Wood, whom Tanner had converted from a reliever to a starter. According to Tommy John, "Tanner never liked to use a knuckleballer in relief, because of the way the knuckler danced and moved all over. He solved that by making Wood a starter." Tanner was voted that year's The Sporting News Manager of the Year Award. He also converted Rich "Goose" Gossage from a starting pitcher to a reliever, a role that led Gossage to the Hall of Fame. He finished his White Sox career with a record of 401 wins and 414 losses. Tanner was replaced by Paul Richards on December 17, 1975. Bill Veeck, who had repurchased the White Sox, invited Tanner to remain in the organization in a different capacity, but the offer was declined. Tanner still had to be paid $60,000 in each of three remaining years of his White Sox contract.

John said that "Chuck Tanner once told me he never forgot the fact that he was a player. When he became a manager, he remembered how he wanted his manager to treat him."
One day later on December 18, 1975, Tanner was hired to succeed Alvin Dark as manager of the Oakland Athletics. With speedy players such as Bert Campaneris, Bill North, Claudell Washington, and Don Baylor, Tanner made the A's into a running team, stealing an AL league-record 341 bases. Eight players had 20 or more steals, including 51 by pinch runners Matt Alexander (who only came to the plate 30 times) and Larry Lintz (who had one at-bat all season). However, the …

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After spending five seasons as a special assistant to the general manager of the Cleveland Indians, Tanner was named a senior advisor to new Pittsburgh Pirates GM Neal Huntington in the autumn of 2007.