She was born Moira Shearer King at Morton Lodge in Dunfermline, Fife, Scotland, the only child of civil Engineer Harold Charles King and Margaret Crawford Reid, née Shearer. In 1931 her family moved to Ndola, Northern Rhodesia, where her father worked as a civil Engineer and where she received her first dancing training under a former pupil of Enrico Cecchetti. She returned to Britain in 1936 and trained with Flora Fairbairn in London for a few months before she was accepted as a pupil by the Russian Teacher Nicholas Legat. At his studio she met Mona Inglesby who gave Shearer a part in her new ballet Endymion, presented at an all star matinee at the Cambridge Theatre in 1938. After three years with Legat, she joined the Sadler's Wells Ballet School. After the outbreak of World War II, her parents took her to live in Scotland. She joined Mona Inglesby's International Ballet for its 1941 provincial tour and West End season before moving on to Sadler's Wells in 1942.