[1] Moxon was born in Wairoa, Hawkes Bay, in 1957, the daughter of Te Muera and Margaret Hawkins.
At age 12 she received a scholarship from the Māori Education Foundation to attend Hukarere Girls' College.
[3] In 2012, Moxon was part of the Ngāti Pāhauwera negotiating team who settled their historical treaty claims with the Crown.
She is a claimant in a number of claims before the Waitangi Tribunal in relation to health, Oranga Tamariki and ACC.
[6][7] Moxon was awarded an Honorary Doctorate by the University of Waikato in 2024 for her contribution to health particularly righting inequities and systemic bias in healthcare.
[11] In 2021, Moxon called for the elimination of state care of children (tamariki) for not upholding Māori self-determination (tino rangatiratanga) over their families (whānau).
[16] Moxon stood as the Māori Party candidate for the Hamilton West electorate at the 2005 general election, gaining 379 votes to finish fifth in a 10-candidate race.
[19] In the 2013 local-body elections, Moxon stood as an independent candidate for the Hamilton City Council for one of six seats representing the West Ward.