Walters began his MLB career as a position player, and appeared in 184 games (177 started) as a third baseman before he converted to full-time pitcher.

He was born in Philadelphia, batted and threw right-handed, stood 6 feet 1 inch (1.85 m) tall and weighed 180 pounds (82 kg).

After getting into 83 games as an infielder (80 at third base) for the Phils, he made his mound debut September 24 by tossing two innings of hitless relief against the Brooklyn Dodgers.

He became a sinker-ball specialist, and after winning 14 games (for a Phillies team that won only 61 contests all year) and leading the National League with 34 starts in 1937, he was traded to the Cincinnati Reds on June 13, 1938.

Retained for 1949, his Reds were 61–90 (.404) on September 27, again lodged in seventh place and 341⁄2 games out of first, when Walters was replaced by Luke Sewell at the club's helm.

He took a leave of absence from his Boston Braves' coaching tenure on June 6, 1952, to serve as the interim manager of the last minor league edition of the Milwaukee Brewers through the end of that season.

Walters then was reappointed the Braves' pitching coach for 1953, with the franchise transferring to Milwaukee during spring training on March 18.

In August 2008, he was named as one of the ten former players that began their careers before 1943 to be considered by the Veterans Committee for induction into the National Baseball Hall of Fame in 2009.