New Royal Bank of Scotland boss Ross McEwan pledged to repay the taxpayer's support by doing "everything possible" to help the UK economy recover, as he began his first day in charge of the state-backed lender.
In a message to staff, he said the bank would put the calamities of the past behind it and made clear that it owed a debt to the public after the Government stepped in to save RBS five years ago, saying it would increase lending.
Mr McEwan said: "We are now faced with an opportunity to build on our progress and create a bank that is known for exceptional customer service and not for failure."
He has already given key endorsement to the Coalition's Help to Buy policy, after announcing at the weekend that the group would back the new mortgage guarantee phase of the scheme as it was brought forward.
The 56-year-old New Zealander was also described today as a "customer banker through and through" by RBS chairman Sir Philip Hampton - as Sir Philip appeared to draw a distinction with the risky practices of the bank's investment arm which took it to the brink.
In a message to staff, Mr McEwan sought to focus on serving households and business through its retail arm, which he has headed for a year since being poached from an Australian bank..
He replaces Stephen Hester, who announced his departure in the summer amid reports of a rift with Chancellor George Osborne.
In his staff message, Mr McEwan made clear that the bank, rescued by the taxpayer at the height of the financial crisis and still 80% government owned, owed a debt to taxpayers.
Mr McEwan said: "It's clear to me that we have a greater obligation than any other bank to build a business that supports its customers.
"We were saved by the Government five years ago because of how important we are to the everyday economy of the UK.
"I want RBS to stand firmly behind its customers with the explicit goal of helping them succeed. That includes an increase in our lending. We must do everything possible to support the recovery and future growth of the UK."
Mr McEwan paid tribute to the "remarkable achievement" of Mr Hester for putting the bank on a stable footing.
His predecessor's departure was said to have come about after he came under pressure from Mr Osborne over the scale and pace of RBS's investment banking restructure.
Mr McEwan faces the challenge of preparing the bank, 80% state owned following its taxpayer rescue during the banking crisis, to private hands.
Its progress to this goal is some way behind Lloyds, whose Government stake has already begun to be sold off.
In a series of tweets today, RBS hailed the arrival of its new chief executive, saying he was having a "busy first day meeting customers and staff".
Mr McEwan spoke to more than 300 employees at an event at RBS offices on London, later visiting entrepeneurs in the Shoreditch area of the capital who are NatWest business customers.
Mr McEwan will be paid £1 million a year plus £350,000 in lieu of a pension.
Married with two children, he joined RBS a year ago from Commonwealth Bank of Australia (CBA) where he was group executive for retail banking services for five years. He previously worked in investment and insurance.
RBS's collapse five years ago followed the disastrous 2007 takeover of Dutch bank ABN Amro, under then-chief executive Fred Goodwin, in a £49 billion deal that weakened its capital position and left it highly vulnerable to the credit crunch.
Mr Goodwin was widely blamed for the catastrophe and later stripped of his knighthood, and Mr Hester was parachuted in, in November 2008, to put the bank back on an even keel.
As Mr McEwan's appointment was announced in August, the bank said it had swung back out of the red with half-year pre-tax profits of £1.4 billion.