Brendan Hamill

Hamill played for the Australian Institute of Sport in the 2009–10 A-League National Youth League where they failed to win a single game. Hamill was selected for the 'Come Play XI' which was thrown together in order to play a friendly against Melbourne Victory as a testimonial game for Kevin Muscat.

Melbourne Heart

On 23 April 2010 Hamill rejected numerous offers from English Premier League clubs to sign his first professional contract with Melbourne Heart along with fellow U-20 players, Kliment Taseski and Eli Babalj. On 5 August 2010, he became the youngest player to play for Heart, at 17 years and 321 days old.

Seongnam Ilhwa Chunma

On 16 July 2012, Hamill joined K-League side Seongnam.

Western Sydney Wanderers

On 26 June 2014, Hamill signed for Western Sydney Wanderers.

Western United

On 15 May 2019, after rejecting a contract extension from Western Sydney Wanderers, Hamill signed for new A-League club Western United.

Melbourne Victory

In July 2021, after playing 20 games over two seasons with Western United, Hamill re-united with coach Tony Popovic, joining Melbourne Victory on a two-year deal.

Mohun Bagan SG

On 23 June 2022, Indian Super League club Mohun Bagan SG announce the signing of Brendan Hamill on a two-year deal. He made his debut for the club as substitute on 20 August against Rajasthan United at the 131st edition of Durand Cup; his team lost the match by 3–2.

In 2009 Hamill was called up to the Australian U-20 squad for the 2010 AFC U-19 Championship qualification as a replacement for the injured Trent Sainsbury. On 7 March 2011 he was selected to represent the Australia Olympic football team in an Asian Olympic Qualifier match against Iraq.

As of 25 November 2021

Mohun Bagan

Indian Super League Shield: 2023-24 Durand Cup: 2023 ISL Cup: 2022–23 Western Sydney Wanderers

AFC Champions League: 2014 Melbourne Victory

FFA Cup: 2021 Australia U-20

AFC U-20 Asian Cup: runner-up 2010 AFF U-19 Youth Championship: 2010 Australia U16

AFF U-16 Youth Championship: 2008