Dion is the Pouwhakahaere (Chief Executive) of Te Kotahitanga o Te Ātiawa Trust, where he is responsible for the strategic leadership and direction of the Post Settlement Governance Entity, managing $140m of assets on behalf of Te Ātiawa iwi.

Dion previously held the role of Chief Executive of Te Ohu Kaimoana from 2016 to 2020 before returning home to Taranaki to take up his current position.  He is an experienced director and is the current Chairman of Parininihi ki Waitōtara Incorporation, former Chairman of Port Nicholson Fisheries LP and former director of Seafood NZ.

Dion commenced in his tenure as Director of Te Ohu Kaimoana in December 2023, and was appointed Deputy Chair in March 2024.