Campion was the only child of George Alfred Hannah (1891—1931), the youngest child of Robert Hannah and his wife Jessie McLean Hannah (née Armstrong).
Robert Hannah founded the R. Hannah and Co. shoemaking business, owning shoe factories and a chain of shops throughout the country. Her father died when she was 8 and her mother 2 years later but her maternal grandmother did not die until 1944. Campion was educated at
Queen Margaret College and
Nga Tawa Diocesan School as well as receiving a private education from governesses. She then travelled with him to London in 1948 to attend the
Old Vic Theatre School, training as an actor. == New Zealand Players Theatre Company ==