This follows a protest by staff at the Māori tertiary institute last year over the board's decision not to renew current CEO, Bentham Ohia's contract.
Mr Mather says the decision was not an easy one and his personal journey at Māori Television is one that will always remain special to him. He expressed his extreme pride in the whānau culture and the support and contribution of staff to the success of Māori Television over the years.
Mather took up the position as CEO of Māori Television in 2005 and has overseen signifficant growth of New Zealand's Indigenous broadcaster including the launch of the Te Reo channel, the establishment of the World Indigenous Television Broadcasters Network (WITBN), coverage of the Rugby World Cup and the annual ANZAC Day broadcasts.
Mr Mather will complete a 6-month notice period before taking up his new role. The recruitment process for a new CEO at Māori Television will begin next month.