[2] Monohan was part of Collingwood's inaugural VFL season, having played four seasons for the club when they were in the Victorian Football Association (VFA).

Renowned for his high marking, he was used mainly as a follower and half back.

Monohan also captained the Victorian interstate football team between 1903 and 1906.

He was the first Collingwood player to play 200 games for the club, with his 236 career games being a club record until it was broken by James "Jock" McHale in the 1915 Grand Final.

His son, Jack Monohan Jr., played for Collingwood in the 1920s.