Mr McEwan immediately sold nearly half of the shares, which RBS said was to settle tax liabilities.
In an announcement to the stock exchange, RBS announced the vesting of 454,106 shares arising from a conditional share award granted on August 2012 as part of the arrangements when Mr McEwan joined RBS from Commonwealth Bank of Australia.
The award was made to compensate him for share awards forfeited when he quit Commonwealth Bank, initially to run RBS's retail banking arm.
RBS revealed he had sold 214,019 shares at 340.2p, raising £728,000. He has retained the remaining 240,087 shares, which he must keep for at least another six months.
The New Zealander took over from Stephen Hester as chief executive in October and pledged he would not take an annual bonus for 2013 or 2014.
However, he could still receive just under £1.4m a year, including £1m in salary, £26,250 in benefits and £250,000 in pension contributions, plus any long-term share awards.