He was still 11 days shy of his seventeenth birthday when he was selected to make his Sheffield Shield debut as a middle order batsman for New South Wales against Victoria in the 1952–53 season. He had played only 12 first grade matches prior to this. When he arrived to meet his teammates, Australian vice-captain Arthur Morris asked him where his nappies were. At the age of 16 years and 354 days, this made him the second youngest cricketer to be capped for New South Wales, just three months older than teammate Ian Craig when he made his debut. He scored 44 and 8, without being dismissed in either innings. According to Haigh, "Great protectiveness was felt towards such a boy among men." From the last ball of a drawn match, Simpson attempted to run two, but his misjudgment saw him caught short by half the pitch. Nevertheless, umpire Hugh McKinnon turned down the appeal, and after Victorian captain Sam Loxton reacted angrily, the arbiter said "it's the last ball of the game and his first match". Simpson took his maiden wicket during the match, catching Test player Ian Johnson from his own bowling.