Leone was born Karen Malhotra in Sarnia, Ontario to Sikh Punjabi parents from India. Her father was born in Tibet and raised in Delhi, while her mother (who died in 2008) was from a small town named Nahan in Sirmaur, Himachal Pradesh. As a young girl, she was very athletic and played street hockey with the boys, enjoyed ice skating on a nearby frozen lake and drinking hot chocolate in front of a fire after playing in the snow all day.