Community services general manager Simon Pickford resigned and was "ready to take up a new challenge", a council spokesman said.
Confirmation of his departure came about a fortnight after it was confirmed infrastructure and development general manager Simon Drew would be leaving to take up a new national role with Fulton Hogan.
Mr Pickford worked for the council for nine years and his responsibilities were library services, parks and recreation, events and community development, museums and galleries.
He was handing over portfolios to other members of the executive, but would continue to work on projects in civil defence and community resilience until his departure in late October, the spokesman said.
Māori, partnerships and policy general manager Jeanette Wikaira would become acting community services general manager and her responsibilities would be picked up by Māori partnerships manager Nicola Morand.
