He was educated at Perth Academy and the University of St Andrews' Queen's College in Dundee,[3] from where he graduated in 1961 with a degree in mathematics and applied physics.
[1] Mathewson started his career as a lecturer at St Andrews University where he did a PhD, before moving to United States to work for Bell Aerospace as an engineer in Buffalo, New York (1967–72).
He was attracted back to Scotland by the opening up of the North Sea to oil exploration and joined venture capital group 3i, then called Industrial and Commercial Finance Corporation (1972–81).
[3] Mathewson joined the Royal Bank of Scotland, which is headquartered in the Scottish capital city of Edinburgh, in 1987 as director of strategic planning and development.
When Mathewson became RBS's chief executive in 1992 the bank had been severely weakened by bad debts arising from poor lending decisions.