The New Zealander is to step down as CEO after leading the bank for more than five years.
The move immediately kicks off the search for a successor, with chairman Sir Howard Davies saying the bank will cast the net internally and externally.
Alison Rose, who in December took up the role of deputy chief executive of NatWest Holdings in addition to her position as RBS’s chief executive of commercial and private banking, is likely to be seen as the leading internal candidate.
McEwan has a year’s notice period and will stay in the post until a successor is appointed.
The announcement came ahead of the bank’s annual general meeting in Edinburgh yesterday, where senior figures at the group told shareholders that concerns over the UK’s departure from the EU will take their toll on the lender’s performance.
Davies said: “The UK economy has proved remarkably resilient but lack of clarity about our future relations with the EU is undoubtedly having an impact, with consumer confidence muted and many businesses pausing on investment. That will affect our income.”
An anticipated shareholder backlash against bosses’ pay did not take place, with all resolutions passed by a majority vote except a move to establish a shareholder committee, which was voted down.
Davies thanked McEwan for his service and contribution to “one of the toughest jobs in banking”.
He added: “His successful execution of the strategy to refocus the bank on its core markets here in the UK and Ireland has helped to deliver one of the biggest UK corporate turnarounds in history.”
McEwan said that he had achieved the strategy set out at the time he joined the group in 2013, having returned the bank to profitability.
Bottom-line profits more than doubled to £1.62 billion in 2018, marking the lender’s second successive year in the black following a decade-long run of losses.
It also announced a £1.6bn final dividend, resulting in a near £1bn windfall for the taxpayer.
RBS was more than 80 per cent owned by the UK government in the wake of the financial crisis, but has since reduced the taxpayer’s stake to 62.4 per cent.
McEwan said: “After over five-and-a-half very rewarding years, and with the bank in a much stronger financial position, it is time for me to step down as CEO.
“It is never easy to leave somewhere like RBS. However with much of the restructuring done and the bank on a strong and profitable footing, I have delivered the strategy that I set out in 2013 and now feels like the right time for me to step aside and for a new CEO to lead the bank.”
RBS is due to report first quarter figures today.