He slumped to an 11–14 mark in 1932, and after beginning 1933 at 0–2 he was traded to the Reds in a six-player deal that brought Leo Durocher to the Cardinals.

On May 24 of that season, he started the first night game in major league history, beating the Philadelphia Phillies 2–1; President Franklin D. Roosevelt turned on the stadium lights from the White House.

In 1940 he was 20–12 with a 3.06 ERA and 115 strikeouts, and threw a pair of one-hitters, as Cincinnati repeated as NL champions; he finished fourth in the MVP voting, with first baseman Frank McCormick taking the trophy for the Reds for the third year in a row (Ernie Lombardi had won it in 1938).

In his final 1945 season, he was 16–11 as the Cubs won the NL pennant, and made three relief appearances in losses during the 1945 World Series against the Tigers.

His 1062 strikeouts with the Reds were the team record until broken in 1948 by Johnny Vander Meer, and remained the top mark by a right-hander until Jim Maloney surpassed him in 1966.