Stewart was regarded by Jim Clark as a highly-strung individual who "at the wheel was as relaxed as anyone". His only appearance in a World Championship Grand Prix came at the 1953 RAC British Grand Prix, in which - due to ignition failure - he failed to finish in his Ecurie Ecosse-entered Connaught-Lea Francis A. Stewart's main competition was as part of the Jaguar racing Ecurie Ecosse team.