Jack Shephard

Dr. Jack Shephard is an American doctor who is the semi-elected leader on the Island. Before Oceanic Flight 815, he was a spinal surgeon at St. Sebastion's Hospital, where his father also worked. He struggled with a marraige with Sarah Shephard, who was a past patient of his. Sarah's back was supposedly irreparable. In one moment though, hje found himself falling in love with another woman and kissed her. He couldn't bear the guilt and confessed to her; that was one of the reason she left. She also left because he worked too much.