The son of major Sylvester Bertram Grimston, George Grimston was educated at Winchester College between 1918-23. Like his father, he joined the Army, serving with the Queen’s Royal Regiment, and he played both hockey and cricket for his regiment. He played club hockey with Teddington, and first-class cricket for Sussex. However, in a 15-year first-class career (1924-39), he played just 26 matches, scoring 826 runs and taking 11 wickets. Grimston coached the Great Britain hockey team to the silver medal at the 1948 Olympics, and served on the England selection committee until 1951. In the 1960s he became secretary of the Sussex County Cricket club.