In 1926, Hallahan pitched in 19 games for the Cardinals during the regular season, and made a first, brief World Series appearance that fall against the New York Yankees.
In the 1930 World Series against the Philadelphia Athletics, Hallahan split two decisions but he shut out the powerful A's in Game 3 and allowed only two earned runs in 11 innings, for a sparkling ERA of 1.64.
In 1931, Hallahan again led the NL in strikeouts (159) and walks (112) and won 19 games, as St. Louis again took the league championship for a rematch against the Athletics.
Hallahan's dominance is even more impressive because the A's featured a predominantly right-handed-hitting lineup, including fearsome sluggers Jimmie Foxx and Al Simmons.
But the Gashouse Gang won the National League title and gave Hallahan one more chance to experience the big stage.
After retiring from baseball, Hallahan worked as a supervisor for General Aniline and Film Co. (now GAF) in Johnson City, New York.
He was a local legend to the young kids in that neighborhood who frequently begged him to show them his World Series watches and rings.