Smyth represented Europe in the Ryder Cup in 1979 and 1981, losing on both occasions to the United States. Smyth also represented his country in the World Cup and the Alfred Dunhill Cup many times and was a member of the Irish team (alongside Eamonn Darcy and Ronan Rafferty) which won the latter in 1988. At the 2006 Ryder Cup, he was one of Ian Woosnam's vice-captains.