[19] On 4 February 2018, Davidson officially announced her candidacy for co-leader,[20] and on 8 April won the female co-leadership election, defeating fellow MP Julie Anne Genter who also contested the position.

[27] Davidson also contested Tāmaki Makaurau, coming third place behind Labour incumbent Peeni Henare and the Māori Party's candidate John Tamihere.

[31][32] Davidson was challenged in May 2021 by the National and Act parties for attending and speaking at a Mongrel Mob gathering at the Waikato Chapters headquarters in Hamilton.

[33] Davidson attended the gathering with fellow Green MP Elizabeth Kerekere and the Human Rights Commissioner Paul Hunt.

[38] Prime Minister Chris Hipkins disagreed with her choice of words but stated that he understood the context she had make the remarks following the motorcycle and Counterspin incidents.

[37] Her message received support from Te Pāti Māori co-leaders Debbie Ngarewa-Packer and Rawiri Waititi, who accused white men of asking her to apologise for her lived experience after having been assaulted.

[39] On 20 June, Davidson was ejected from House proceedings after claiming that ACT MPs were promoting racism through their line of questioning during a debate about national health service Te Whatu Ora's new "Equity Adjustor Score."

Several ACT MPs including Karen Chhour and James McDowall claimed that the Equity Adjustor Score favoured Māori and Pasifika patients over other ethnic groups.

After official results were released, Davidson said the party would "lead the ongoing fight to eliminate poverty, honour Te Tiriti, protect nature, and build a climate-resilient future for our mokopuna".

[46] On 5 June 2020, Davidson and fellow Greens Co-Leader James Shaw described United States President Donald Trump as a racist in response to a question fielded by press gallery journalists following the protests triggered by the murder of George Floyd in late May.

Other passengers aboard included the Nobel Peace Prize laureate Mairead Maguire and retired US Army colonel Ann Wright.

In response to the boarding of the Women's Peace Flotilla, Green Party co-leader Metiria Turei called on the Israeli authorities to release Davidson and other activists, and to end the blockade of Gaza.

[51][52][53] Davidson is a qualified aerobics instructor and used to teach part-time classes at Les Mills International in order to support her children and university studies.

[22] In late June 2018, Davidson disclosed that she had been sexually abused as an eight-year-old child by a distant relative during a Speaking Secrets podcast, a co-production by The New Zealand Herald and Newstalk ZB.