Leggett was born in Porirua City in 1979 and grew up in Whitby, Plimmerton, Papakowhai, and Paremata.

He was educated at Paremata School and Tawa College, and then studied at Victoria University of Wellington, graduating with a BA in political science.

[12] Although a member of the New Zealand Labour Party throughout his career in local body politics,[13] Leggett stood as an independent candidate.

[14] In April 2016, he resigned from the Labour Party to run for Mayor of Wellington as an independent; Justin Lester had already been selected as the official Labour candidate and it is against party rules for members to compete against officially endorsed candidates.

[16] In August 2016, Labour Leader Andrew Little accused Leggett of being a "right-winger", alleging that his campaign manager for the Wellington Mayoral election was a well-known ACT Party figure.

[19] Leggett later abandoned his plans to run for Parliament but stated he would still campaign for the National Party in the area.