Playing for King Cross Park RLFC a Halifax based community club as a junior which he is still heavily involved in. He joined Bradford Junior Development system and was called up to the England Knights in 2019 along with 3 other Giants players.[4]
Playing career
Bradford Bulls
O'Brien featured in the pre-season game against Dewsbury. O'Brien was not selected in any league or cup matches this season. At the end of the 2010 season he was given a three-year professional contract.[citation needed]
O'Brien featured in three of the four pre-season friendlies. He played against Castleford, Dewsbury and Hull F.C. O'Brien featured in Round 19 (Wigan) to Round 21 (Leeds).
He signed a five-year extension to his contract midway through the season.[citation needed]
O'Brien featured in the pre-season friendlies against Dewsbury and Leeds. He featured in Round 5 against Huddersfield and then in Round 7 against Hull Kingston Rovers. O'Brien also featured in Round 10 against Salford and Round 17 against Hull Kingston Rovers. His next appearance was in Round 25 against Castleford to Round 27 Huddersfield. O'Brien featured in the Challenge Cup against the Rochdale Hornets.[citation needed]
O'Brien featured in the pre-season games against Hull F.C. and Castleford.
O'Brien re-signed with Bradford for another two years despite their relegation to the Championship for the 2015 season.
O'Brien featured in the pre-season friendlies against Castleford and Leeds. He featured in Round 1 Leigh to Round 23 (Halifax). O'Brien played in Qualifier 1 against the Sheffield Eagles to Qualifier 6 (Leigh Centurions). O'Brien played in the £1 Million Game against Wakefield Trinity. He also featured in the Challenge Cup in Round 4 Workington Town to Round 5 Hull Kingston Rovers. At the end of the 2015 season O'Brien won the T&A player of the year, the Bradford members player of the year and Bradford Players' player of the year.[citation needed]
O'Brien featured in both pre-season friendlies against Leeds and Castleford. He featured in Round 1 Featherstone Rovers to Round 22 Oldham. Adam played in the Championship Shield Game 1 Whitehaven to the Final Sheffield Eagles. Midway through the season O'Brien signed a contract extension keeping him at the club until the end of 2019.[citation needed]
Following Bradford's liquidation prior to the 2017 season, O'Brien signed a three-year deal following teammate Alex Mellor to Huddersfield in the Super League.[5] In the 2018 Super League Season Adam O'Brien received the Huddersfield Giants Players Player of The Year Award. In January 2019, O'Brien signed a new three-year deal until the end of 2022.
Halifax Panthers
On 5 October 2023, it was reported that he had signed a 3 year permanent deal with his hometown club Halifax commencing the 2024 season.[6]
O'Brien appeared as an interchange in a victory against France U18 in June 2010 and in both tests against the Australian Schoolboys in December 2010, England Academy won the series 2–0 with both games being played at Leigh Sports Village.[citation needed]