Le Couteur was born at Kyneton, Victoria, the only son of George, a pharmaceutical chemist, and his wife Fanny.
After beginning a medical degree in 1907 Le Couteur won the Victorian Rhodes Scholarship for 1908 and, with a Melbourne Master of Arts, proceeded to University College, Oxford.
He won an Oxford cricket blue and in 1911 a place in Wisden for making 160 runs and taking 11 wickets for 69 against Cambridge.
For ten years Le Couteur served on various university committees and school councils and captained the Hawthorn-East Melbourne Cricket Club.
Le Couteur's term at Newington covered the difficult Depression and war years, yet saw a remarkable increase in pupils and the opening of a preparatory school, Wyvern House, in 1938.