Smithson was a left-handed middle-order batsman, a medium pace bowler and a highly agile and effective fielder of the ball.
Cricket historian Alan Hill (author) wrote that this particular innings "aroused hopes of an exciting future" and compared the style of the later England left-hander David Gower to that of Smithson.
Conscripted into National Service as a Bevin Boy in the coal mines during World War II, he worked for three years at Askern Main Colliery in South Yorkshire, before receiving special permission (after his case had been debated in the House of Commons) for temporary release so that he could join the tour to the West Indies with the Marylebone Cricket Club (MCC) team of 1947–48.
He was not successful in the first game, but made 35 in each innings of the 2nd Test, and his durability at the wicket helped to save the match for England.
In 1949, Smithson was part of Norman Yardley's side that won the County Championship, sharing the title with Middlesex.