[4] Of Māori descent, he affiliates to the Te Āti Awa, Ngāti Mutunga and Ngāi Tahu iwi.
Tamati played for the Waitara Bears and represented Taranaki locally before being selected for the Kiwis in 1979.
[10][11] Tamati currently serves as the Chairman of the New Zealand Māori Rugby League starting in 2004.
He is the former chairman of Te Ihi Tu Maori Prisoner Habilitation Centre in New Plymouth.
[5][17] In 2016 he announced he would not seek re-election to the council in 2015 and won the Māori Party nomination for the Te Tai Hauāuru electorate in the 2017 New Zealand general election.
[4] In the 1994 New Year Honours, he was appointed a Member of the Order of the British Empire, for services to rugby league.