After joining the Leopards from Castleford Tigers, Gareth has played a huge part in the club’s successes over the past two seasons and again will have an important part to play in 2025. He played a pivotal role from fullback in the 2023 Challenge Cup Final victory over Hull KR.

An extremely talented player whom Leopards’ head of rugby Chris Chester previously tried to sign on numerous occasions, he is equally as comfortable at either a fullback role on in the halves and is a tough, brave player who fronts up very well defensively and has a high percentage goal-kicking record.

A product of the Warrington academy, O’Brien had a professional debut to remember as he scored a try in the Wire’s 80-0 Challenge Cup win over Keighley in 2011. In his five-year stay at Warrington, which included loan spells at Widnes Vikings, Swinton Lions, Castleford Tigers and St. Helens O’Brien racked up 62 appearances with 19 tries and 81 goals.

He also featured in the 2015 World Club Series against St. George Illawarra Dragons, where he scored a try and kicked two goals in Warrington’s 12-18 defeat at the Halliwell Jones Stadium.

After his release from the Wolves at the end of the 2015 season, O’Brien signed for Salford Red Devils. In his first season at Salford, he was a regular in Ian Watson’s side, culminating in the 2016 Million Pound Game against Hull KR. O’Brien kicked an extraordinary drop goal from the halfway line in golden-point extra time to keep Salford in the top tier.

In 2018, O’Brien moved to Toronto Wolfpack, where he proved to be a prolific points-scorer. In the 2019 season he scored 20 tries and kicked 99 goals as he helped guide them to Super League for the first time. As a result of his exploits on the field for the Wolfpack that season, O’Brien was named 2019 Championship Player of the Year at the end of season awards.

O’Brien went on to join Castleford Tigers on an initial loan in 2020, following Toronto’s withdrawal from the Super League competition, which subsequently was made a permanent deal the season afterwards. He passed a landmark of 300 career appearances late in the 2024 season when his thrilling try clinched Leopards’ first play-off win of the Super League era at his old club Salford.