Stewart scored 84 goals, all but six being penalties, in 434 games for West Ham. Despite playing in defence he was sent off only twice in his West Ham career, neither for fouls committed but on both occasions for comments made to referees or linesmen in games against Aston Villa and Liverpool. In all of West Ham’s three FA Cup triumphs, 1964, 1975 and 1980, he is also notable as the only non-English player to appear in any of the West Ham winning teams. He became a favourite with the fans who nicknamed him "Tonka" after Tonka Toys, which were described as 'indestructible'.