George is the older brother of Toby King: they both played their amateur rugby league at Meltham All Blacks, and George additionally played for Siddal. They were spotted by the Wires’ Yorkshire scout Tommy Gleeson after both appeared for Huddersfield.[citation needed]
In September 2020 the club web site announced the signing of King from Wakefield Trinity[11]
King played a total of 20 games for Hull KR in the 2021 Super League season including the club's 28-10 semi-final loss against the Catalans Dragons.[12][13][14]
On 12 August 2023, King played for Hull Kingston Rovers in their 17-16 golden point extra-time loss to Leigh in the Challenge Cup final.[15]
King played 27 games for Hull Kingston Rovers in the 2023 Super League season as the club finished fourth on the table and qualified for the playoffs. He played in the clubs semi-final loss against Wigan.[16]
Huddersfield Giants
On 17 October 2024 it was reported that he had signed for Huddersfield in the Super League on a four-year deal.[17]