King attended Hamilton Boys' High School and completed an apprenticeship in combustion engine reconditioning before training as an electrician and working self-employed.

[2] King ran for the Hamilton City Council in the West ward with his son Josh on the "Two Generations" ticket in the 2013 elections.

[8] King ran for a second term in the 2019 Hamilton mayoral election, he was challenged by City Councillor Paula Southgate, who he had defeated by just six votes in 2016.

He defended the rates rises that occurred during his mayoralty, citing them as necessary to fixing the city's finances, saying "I'm very proud of what we've done and what we've achieved, and there was a price to pay for that – and that was my job.

He wouldn't confirm whether he stood aside voluntarily or at the direction of the party, which was operating under expectations from leader Christopher Luxon to improve the diversity of its candidates.