"So this is also a great opportunity to reconnect and to bring back a lot of the things I have learnt at the Sarjeant and at other places to the Auckland Art Gallery and play a useful part in its future.
"It's been a great 15 years and the Sarjeant's best day is ahead of it."
Anderson said the Sarjeant Gallery was in a good state and was well operated.
"The redevelopment is happening at pace under the proper direction of Gaye Batty and the council's chief executive so I felt comfortable enough to apply for and accept the role at Auckland Art Gallery."
He said the most important thing to him in his role was making sure the redevelopment project actually went ahead.
"The fact that I won't be the person necessarily cutting the ribbon is fine. I'm very comfortable knowing the work we did has ensured the gallery's future."
The Whanganui District Council's general manager of community and customer experience Marianne Cavanagh said Anderson played a key role in the Sarjeant Gallery Redevelopment project.
"Greg was at the forefront of fundraising for the redevelopment, in partnership with the chair of the Sarjeant Gallery Trust, Nicola Williams," Cavanagh said.
"Together they raised and secured tens of millions of dollars towards the strengthening and extending of the historic gallery – and its future is now assured."
Whanganui District Council chief executive David Langford said the recruitment process for the new Sarjeant Gallery director was already under way.
Anderson's last day at the Sarjeant Gallery will be October 14.
