Katherine Rosaleen Mills was born in 31 South Square,
Inchicore,
Dublin, on 8 October 1923. Her mother, Winifred (née Wills), was from Inchicore and her father, Thomas, was from Glanmire, County Cork. Her father worked for Great Southern Railways. She had three siblings, Gertrude, Ada and Robert. When she was just eighteen months old her mother died, leaving her to be raised by her maternal grandmother, Charlotte Wills, who lived 1 Abercorn Terrace, Inchicore. She was educated in the local convent school at
Goldenbridge, where she played table tennis and soccer as well as doing gymnastics. However,
camogie was her first love, which she started playing at age 5. She left school at a young age, and went to work in Lamb's jam factory. Through her father, Mills was able to participate in and avail of the sporting activities in the GSR Athletic Union. Two pence per week were deducted from the worker’s wages to go towards the financing of the sports activities in the Railway. In 1947, Mills married George Hill. They ran the Red Seal Handbag Company from the North Circular Road, and later Hill Street. Later they became vintners, running the Seventh Lock public house on the Grand Canal,
Ballyfermot. ==Playing career==