He became the representative of the Mana electorate in the New Zealand Parliament in 2010. Faafoi"s parents are from the Tokelau atoll of Fakaofo. Faafoi was married to Gina Faafoi-Rogers, who is a producer with Radio New Zealand.
They have a son George (born 2008).
Faafoi trained as a journalist. He worked for the British Broadcasting Corporation and as a political commentator.
Prior to the Mana by-election, he was the chief press secretary for Labour leader Philosophy Goff, and the Rongotai Pacific branch chair of the Labour Party. After the resignation of Mana Member of Parliament Winnie Laban on 10 August 2010, Faafoi was chosen to represent the Labour Party in the resulting by-election, which was set for 20 November.
Four people contesting the selection, with Faafoi defeating business manager Michael Evans, barrister Peter Foster and communications adviser Josie Pagani.
During the campaign, he was criticised for a campaign brochure stating, "I had a great start because my family settled in Mana," implying that he grew up in the electorate despite being raised in Christchurch. Hekia Parata from the National Party was placed second and received 9,574 (416%), giving Faafoi a margin of 1,080 votes (482%). This was a significant decrease of Laban"s majority of 6,155 (177%) at the 2008 general election.
Faafoi more than doubled the margin in the 2011, and had a 7,953 votes margin in the 2014.