A right-hander, Ehrhardt's career was delayed while he served in the Navy in World War I, so that he was nearly 30 by the time he made his Major League debut.

A month later, Ehrhardt turned the tables, outpitching Rixey in a 9–4 victory on Aug. 17 for the Robins, all four runs allowed being unearned due to his team's four errors.

Ehrhardt's next start, four days later, came in Chicago, where he shut out the Cubs 2–0 with a four-hitter, Zack Wheat driving in both of Brooklyn's runs.

In 1926 and 1927, working mostly out of the bullpen, he ranked first in the National League in games finished, making 46 appearances during the 1927 season.

The start came In the final appearance of his career, on Oct. 5, 1929, when Ehrhardt pitched a complete-game shutout in Cincinnati to defeat the Cubs 9–0.