Former Waikato-Tainui leader Tukoroirangi Morgan says his greatest achievement was settling a treaty claim over the Waikato River.
The iwi reached a Deed of Settlement in August 2008, and it was passed into legislation in 2010.
The legislation underpinned the Waikato River Authority, and provided for a $210 million clean-up fund for the Waikato River for the next 28 years.
A former chairperson of the Tainui executive, Mr Morgan says he decided not to put himself forward for the final seat on the latest executive because he is considering other job prospects.
The former leader says his most prized memory as executive chairperson is working with the late Lady Raiha Mahuta on the river claim.
The settlement led to a new era of co-management as Waikato-Tainui tribes and the Waikato Regional Council work together in the Waikato River Authority to co-manage the river, he says.