Grimmett was a New Zealander by birth — Caversham, near Dunedin, 1891 — who had moved to Sydney in 1914 and to Melbourne in 1917 before settling in Adelaide in 1924. He played his first Test for Australia at 33 in 1924-25, taking 11 wickets in his debut match against England. He was a small, slight leg-spinner who bowled flat, accurate, with subtle variation; his stock ball was the slow leg-break, his weapon was the flipper — a delivery he claimed to have invented in 1934 and which Shane Warne would later credit Grimmett with creating.
Through the 1930s Grimmett carried Australia's spin attack with O'Reilly. The two formed the most successful spin pairing in Test history at that point, taking 169 wickets in series in which they bowled together. In South Africa 1935-36, the last tour of his career, Grimmett took 44 wickets in five Tests — still the Australian record for a Test series — at 14.59. He passed 200 Test wickets in his last Test innings at Durban.
Despite the South African feat, the Australian selectors dropped Grimmett from the 1936-37 home Ashes side and from the 1938 tour of England. Bradman, by then captain, was widely believed to have favoured younger spinners; Grimmett never publicly forgave him. He played on for South Australia until 1940-41 and finished his first-class career with 1,424 wickets at 22.28.