Jock O'Brien was an Australian rules football

Australian rules football

Australian rules football, officially known as Australian football, also called football, Aussie rules or footy is a sport played between two teams of 22 players on either...

er who played with Essendon

Essendon Football Club

The Essendon Football Club, nicknamed The Bombers, is an Australian rules football club which plays in the Australian Football League...

 in the Victorian Football League

Australian Football League

The Australian Football League is both the governing body and the major professional competition in the sport of Australian rules football...

 (VFL).

O'Brien played his junior football for Essendon but was recruited from Williamstown

Williamstown Football Club

The Williamstown Football Club, nicknamed The Seagulls, is an Australian rules football club based in Melbourne and are currently playing in the Victorian Football League...

. He was used as wingman and rover. He won the award for Essendon's "best first year player" in 1932 but after two more seasons had to retire, due to work commitments.

He was the elder brother of North Melbourne

North Melbourne Football Club

The North Melbourne Football Club, nicknamed The Kangaroos, is the fourth oldest Australian rules football club in the Australian Football League and is one of the oldest sporting clubs in Australia and the world...

 captain Dally O'Brien

Dally O'Brien

Dally O'Brien was an Australian rules footballer who played with North Melbourne in the VFL during the 1940s.O'Brien played 137 games for North Melbourne and was club captain in 1944 and 1945. He won their best and fairest award in 1948, also finishing equal 8th in the Brownlow Medal...

.