Joseph, of Ngāi Tahu, Te Ati Haunui-A-Pāpārangi, Ngāti Rangi, holds master's and doctoral degrees from the University of Canterbury and the Auckland Institute of Technology.
Joseph is a registered social worker and is involved in a number of governance roles locally, regionally, and nationally. These include the Aotearoa New Zealand Social Workers Association, Purapura Whetu Trust, Presbyterian Support, Ngā Pou Mana - Tangata Whenua Allied Health, STOP, Te Aitarakihi Marae-A-Iwi, Waitaha Māori Rugby, Canterbury Mens Centre, Hope Upstream Charitable Trust, Health Promotion Forum New Zealand, Ministry of Health Social Work Reference Group, Lyttelton Recreation Trust, and Board of Trustee’s Te Kura o Manga o Kawari.
Joseph is a former staff member at Te Otū Mātua and is a current volunteer youth worker for Lyttleton Recreation Centre Youth Group where he has been involved since he was 17.
Joseph is employed by Te Aka Whai Ora as the Investment and Infrastructure Lead and is an adjunct lecturer in social work at Te Pūkenga.