Maroney was born with cerebral palsy. She initially kept her condition secret, but in 2007 she and her mother Pauline revealed her condition on the TV talk show "Enough Rope". She was four years old when she started swimming, and by the time she was seven years old she was competing in swimming carnivals. Before that she only competed in short distance events. After turning 13 years old she came to realise that she could do long swims. After failing to graduate from high school she pursued her vocation.