Born in Kawakawa on 2 March 1967,[1] and raised at Karetu in the Bay of Islands,[2][3] Davis affiliates to the Ngāpuhi iwi and the Ngāti Manu hapū.

Davis stood for the seat in the November 2011 general election, but placed second to Harawira for a third time and also failed to re-enter parliament from the party list.

[4] Shane Jones then resigned from Parliament months prior to the election, and Davis assumed his place in the House of Representatives on 23 May 2014, as he was by then the highest-ranking non-MP on Labour's 2011 party list.

[20] In 2015, he criticised private prison provider Serco's management of inmates, alleging 'corruption' at the Mount Eden remand facility.

[21] Following an inquiry, Serco lost its contract to run the facility and Minister of Corrections Sam Lotu-Iiga was relieved of his post.

[22][4] Davis also criticised the Australian government for its incarceration of New Zealand expatriates facing deportation and visited a detention centre on Christmas Island.

[29] On 1 September 2017, Ardern corrected Davis after he publicly said that Labour would campaign on a capital gains tax policy during the 2020 general election rather than implementing it mid-term.

[31][32] On 19 September, Davis indicated that he was willing to sacrifice his potential position as deputy prime minister in order for Labour to form a coalition government with either New Zealand First or the Green Party.

[33] In the 2017 general election, Davis was re-elected in Te Tai Tokerau, defeating Mana Movement leader Harawira by 4,807 votes.

[35] Labour continued as a majority government after the 2020 general election, in which Davis won a third term as Te Tai Tokerau MP over new Māori Party candidate Mariameno Kapa-Kingi.

"[41] In 2020, Stuff further reported, "it is widely considered, on both sides of the House, that he underperforms when put under the media or parliamentary spotlight" and described finance minister Grant Robertson as Ardern's de-facto political deputy.

He oversaw the establishment of a new government department, Te Arawhiti, the Office for Māori Crown Relations, in 2018 to lead the portfolio's work and held a series of hui to determine its focus.

"[45] In 2018, after his first year in the portfolio, Davis was praised by political scientist Bronwyn Hayward, who said that although his work was "below the beltway of gallery commentary... outside the Wellington bubble, he has been everywhere: visiting marae, listening, rebuilding trust.

[49] However, Davis was accused by his National Party counterpart Mark Mitchell of focusing on emptying prisons rather than reducing crime.

[50] The Corrections Minister's silence during the five-day standoff drew criticism from the National Party's corrections spokesperson Simeon Brown and Māori Party co-leader Rawiri Waititi, with the former criticising Davis' alleged lack of leadership and the latter saying that the prisoners were protesting their right to basic needs such as clean water, insufficient clothing, and washing facilities.

He also said that "[the men] damaged property worth hundreds of thousands of dollars, and they put their own lives and the health and safety of staff and other prisoners at risk.

[54] He refused to express confidence in its chief executive, Grainne Moss and met with the public service commissioner about the future leadership of the agency.

[56] Soon after, Davis announced a ministerial advisory board that would investigate Oranga Tamariki's criticised policy of uplifting children from their families.

[57] Following the board's advice, Davis began reforms to devolve Oranga Tamariki services to iwi and community providers.

[65] During the 2023 New Zealand general election, Davis lost his Te Tai Tokerau seat to Māori Party candidate Mariameno Kapa-Kingi by a margin of 517 votes.