Walters broke into pro baseball as a pitcher/third baseman in 1929 but played only the infield from 1930 through 1933. He failed in trials with the Braves in 1931-32 but batted .376 in the Pacific Coast League in 1933 to earn a shot as a third baseman with the Red Sox in 1933. It wasn’t until he was sold to the Phillies in 1934 that Walters reverted to pitching at the suggestion of manager Jimmie Wilson, a veteran catcher.
The Phillies of the 1930s were losing ballclubs, and in 1936 Walters was the National League‘s biggest loser, going 11-21. He led the league with 34 starts in 1937, winning 14, and was traded to the Reds in 1938. The sidearming flamethrower, who relied almost exclusively on a sinking fastball, then helped Cincinnati to two straight pennants, going 27-11 in 1939 and 22-10 in 1940. In each season he led the NL in wins, ERA, complete games, and innings pitched. In 1939 he tied Claude Passeau for the league lead with 137 strikeouts. For his performance in 1939, he was named the NL’s Most Valuable Player, the second of three straight Reds to win the award.
When the Yankees swept Cincinnati in four games in the 1939 World Series, Walters started and lost Game Two and was the loser in relief of the final game, the victim of four Cincinnati errors. In the 1940 WS, he twice defeated the Tigers, throwing a three-hitter in Game Two and a five-hit shutout in Game Six.
Walters had one more superb season in 1944, winning a league-high 23 games while losing only 8, and compiling a career-best 2.40 ERA.
Walters replaced John Neun as Cincinnati’s manager during the 1948 season and was relieved by Luke Sewell late in 1949 with the team in seventh place. He coached for the Braves and Giants through 1957.