DeLauren McKnight was surprised to learn she was a match for her father, Billy Houze, as they are not blood-related.
Mr Houze’s kidneys began failing in 2016. Doctors said he would not survive past five years without a transplant.
None of the 64-year-old pastor’s other family members had been a match.
Speaking on Good Morning America on Friday, Mr Houze, a father to five children, said he was “extremely proud” of his daughter.
“She told me, ‘Daddy, you thought you were saving my life pulling me from foster care but in actuality, you were saving my life so I could save yours later.’”
The Baptist pastor began suffering kidney failure following a gall bladder surgery in 2016. When none of his relatives were donor matches, doctors said it could take him seven years to get a kidney.
Then, in February, they tested Ms McKnight, who Mr Houze and his wife adopted in 1992 – and she was a perfect match.
When Ms McKnight told him the unexpected news, she said her father broke down in tears.
“I call him my Superman,” she told Good Morning America. “There’s nothing in this world I wouldn’t give him so he can enjoy life and be right there beside me.”
Mr Houze and Ms McKnight will be undergoing surgery in the next few weeks.