Baker served as interim manager after Harris resigned with two games to play in the 1933 season, then returned to coaching third base under Harris' replacement, player-manager Mickey Cochrane. The Tigers won back-to-back AL pennants in 1934 and '35, and their first ever World Series title in 1935. Baker managed the team again in mid-1936, when Cochrane took a leave of absence due to what was described as a "nervous breakdown"; and again in mid-1937 after Cochrane suffered a fractured skull when he was hit by a pitch. In 1938, the Tigers compiled an early-season record of 47-51; on August 7, Baker replaced Cochrane as manager. He rallied Detroit to 37 wins in 56 games, enough to finish in the first division, but Detroit slipped to fifth in 1939.
In 1940, the New York Yankees, who had won the AL pennant and the World Series four years running, faltered, leaving the Tigers and the Cleveland Indians to contend for the league title. On the final day of the season, with the two teams tied, Baker chose obscure rookie pitcher Floyd Giebell to pitch for the pennant against future Hall of FamerBob Feller. The Tigers won the game and the pennant, 2–0; but in the World Series, they lost in seven games to the Cincinnati Reds, despite Bobo Newsom's heroic pitching performances. With World War IIon the horizon, the 1941 season was marked by the call to active military service of numerous baseball stars, including Greenberg. With their star power hitter out of the lineup, and Newsom ineffective, Detroit fell below.500 that season, and again in 1942. Baker was replaced after the 1942 season by Steve O'Neill.
Later career
Baker returned to the coaching ranks with Cleveland and the Boston Red Sox. From 1949–51, he served as skipper of the Sacramento Solons and the San Diego Padres of the Pacific Coast League. In his final season, 1960, Baker managed one last time in the big leagues as Boston's interim pilot from June 8–12 between Billy Jurges' firing and Pinky Higgins' rehiring. Under Baker, the last-place Red Sox won two games and lost five. He retired from the game after his 50th season in baseball, his last day overshadowed by Ted Williams' last game as a player. Baker died at age 81 in Olmos Park, Texas.
Sign stealing
As a coach and manager, Baker was known for his proficiency at detecting the type of pitch an opposing pitcher was about to deliver and tipping off his team's batter with verbal signals. He carefully observed each pitcher's idiosyncrasies, looking, he said, "for all the little quirks, details and tell‐tales." He found that many pitchers concealed the ball poorly before delivery, allowing him to see their grip. Others telegraphed their curve balls by bending their wrists, or subtly altering their wind‐ups. "There are also facial telltales. I know pitchers who, when they throw a curve, bite the lip or stick out the tongue," he said. Tigers shortstop Dick Bartell wrote that the Tigers were unusually successful against Feller in 1940 because Baker was reading all of Feller’s pitches. Among Detroit hitters, it was said that Greenberg was the biggest beneficiary of Baker's tip-offs, although Greenberg himself said that "the importance of such information... has been exaggerated." Another apparent beneficiary was Don Larsen, who wrote in his memoir: In response, Larsen adopted a "no-windup" delivery, which he used in the 1956 World Series to pitch the only perfect gamein Series history, in Game Five.
