Natalie Mackenzie is Mac's non-biological mother. She and her husband take Mac in by accident after the hospital accidentally switches her with Madison Sinclair. The families are later notified and won a million dollar lawsuit. Instead of returning Mac to her real family, they decided to keep her and seem to enjoy being with her and shows no signs of wanting to know more about their real daughter, Madison.
Though the Sinclairs used the money they got wisely and flourished into a rich family, the Mackenzies business quickly flopped and soon lost hold of their business. They remain a middle class family and humble.