In the first professional league season, he played shortstop in five games for the 1871 Fort Wayne Kekiongas.

[2] During that stretch, he played a few professional games for the 1871 Fort Wayne Kekiongas of the National Association.

When the Reds disbanded during business troubles, it looked as if the team was going to fold; he and Charley Jones agreed to sign and play with the Chicago White Stockings.

The two teams agreed that Jones would return to the Reds while Hallinan would remain with the White Stockings.

[4] During July of 1878, Hallinan became too ill to play, which forced him to quit,[2] and although he returned to the field later in August for the Indianapolis Blues, he was only able to participate in three games.