Mahoney was born in Nambour, Queensland, Australia and played junior rugby league for Kawana Dolphins.

[citation needed] Mahoney started his football in Queensland, playing for the Kawana Dolphins and Beerwah Bulldogs as junior.

The following week, Mahoney was placed on report and suspended for one match after being cited for a dangerous tackle in Parramatta's 42-24 loss against Souths.

Due to injury, Mahoney was made the starter at hooker for the remaining five games of the 2018 season, expressing his desire to re-sign with Parramatta.

[citation needed] On 22 April 2019, Mahoney scored a try on his 21st birthday as Parramatta defeated Wests Tigers 51-6 in the opening NRL game at the new Western Sydney Stadium.

[7] Mahoney made 26 appearances for Parramatta in the 2019 NRL season as the club finished 5th on the table and qualified for the finals.

Mahoney scored the first try of the 2020 NRL season as Parramatta defeated arch rivals Canterbury-Bankstown 8-2 at Western Sydney Stadium.

[12] On 1 June, Mahoney was released from the Queensland camp and subsequently named in Parramatta's round 13 match against Newcastle.

[19] In round 1 of the 2023 NRL season, he made his club debut for Canterbury in their 31-6 loss against Manly at Brookvale Oval.

[22] Mahoney played a total of 25 games for Canterbury in the 2024 NRL season as the club qualified for the finals finishing 6th on the table.