Debbie Crosbie has been appointed chief executive of the TSB as the crisis-hit bank looks to move on from an IT meltdown which caused chaos for thousands of customers.
Her appointment follows the departure in September of Paul Pester, who left TSB in the wake of the IT failure.
Gerry Mallon, a Belfast man and former Danske Bank chief who is now leading Tesco Bank, had also been linked to the role.
Ms Crosbie joins from CYBG, where she spent 20 years, most recently as chief operating officer, and will begin her new role in 2019.
Chairman Richard Meddings said that, under her leadership, the bank will focus on "putting things right for customers".
He added: "In an impressive field of candidates, Debbie stood out. With over two decades of experience, superb retail and SME banking expertise, and a genuinely open and engaging style of leadership, we have found an outstanding new CEO."
Ms Crosbie will become one of the few women to lead a British bank. TSB did not disclose her salary but said she will be paid more than Mr Pester.