Ethan and Candice Hart were married in the early 1980s, and shortly after welcomed a baby girl, Zoe, into the world. Zoe and Ethan were very close during her childhood years- Zoe even adopted dreams of becoming a cardio-thoracic surgeon like him, with the ultimate goal of becoming his partner. She was determined to follow in Ethan's footsteps, even performing her residency at New York Hospital, the same hospital where he had performed his, despite her mother Candice's attempts to sway her in another direction.
However, when Zoe was ten years old, she had an accident where she fell off a swing, and the doctors thought she might need a blood transfusion. When Ethan tried to donate blood, and proved not to be a match for his daughter, it was revealed to him that he was not Zoe's biological father, and that shortly before their marriage, his wife had had an affair with older southern gentleman Harley Wilkes while on a Greek cruise. Described by Candice as a man who "can't deal with complications" (Pilot), this revelation was difficult for Ethan to deal with, and he soon left his family, divorcing Candice Hart. He apparently attempted to remain a part of Zoe's life (who still believed him to be her father) for a time, but found it difficult and became very distant from her.
Zoe would not discover the truth of her paternity until she was 28, after moving to Bluebell, Alabama and receiving a photograph of Harley Wilkes and her mother together. Candice confirmed that Harley was her father, and that Ethan had learned the truth when she was ten- Zoe would refer to this as "why Dad stopped loving me" (Pilot).