Announcing the appointment yesterday, trust chairwoman Tamsin Orr-Walker, of Gibbston, said enlisting Mr Hillary's help to raise awareness of the importance of saving kea was a "major boon''.
He was the guest speaker at a kea convention the trust held in 2017, and she was excited to have him on the team.
Kea were facing many challenges in an environment increasingly modified by human activity, so protecting the species was a challenge for all New Zealanders, Ms Orr-Walker said.
Mr Hillary said kea were a symbol of the Southern Alps, and it was "abhorrent to think of our mountains without them''.
"That is why I see the work of the Kea Conservation Trust and its partners as so important.
"I love our mountains and natural environment, and for me the call of a kea up at the snow line is one of the thrills of being in the Southern Alps.''
Kea are endemic to the Southern Alps, and the world's only mountain parrot. They are classified as nationally endangered, an estimated 3000 to 7000 living in the wild.
Mr Hillary is the son of the late Sir Edmund Hillary.
