TSB chair John Kelly said Cooper brought the right range of skills and experience needed as the bank implemented its growth strategy and continued to evolve to meet the changing banking landscape.
"Our priority in appointing TSB's new CEO was demonstrable leadership capability to contribute to our vision, drive strategy execution through technology and customer-led innovation, and build relationships with all of the bank's stakeholders.
"The appointment of Ms Cooper to the role ticks all of those boxes. It also enables us to benefit from a fresh perspective at a time when the spotlight is on banks to put customer interests first," Kelly said.
Banks have come under the eye of regulators in New Zealand this year in the wake of Australia's Royal Commission into misconduct in the financial services sector and are also facing pressure from technology changes.