<Tr> <Th> Nationality </Th> <Td> American </Td> </Tr> <Tr> <Th> Former residence </Th> <Td> California, USA </Td> </Tr> <P> Dr. Christian Shephard is a fictional character on the ABC television series Lost played by John Terry . He is the father of lead characters Jack Shephard (Matthew Fox), who becomes the de facto leader of the survivors of Oceanic 815 after it crashes on an island, and Claire Littleton (Emilie de Ravin), another of the survivors on the Island . Christian died of an alcohol - induced heart attack days before the flight, leading to much of his story being told through flashbacks . In the fourth season and fifth season he is again featured on the Island several times, seemingly acting as a messenger for the leader of the Others, Jacob (Mark Pellegrino). In the sixth season, the Man in Black (Titus Welliver / Terry O'Quinn) admitted that he had "impersonated" Christian during the first week after the crash of Flight 815 . </P> <P> Christian is introduced in the fourth episode of the series, and goes on to feature in thirteen more, including a pivotal scene in the series finale, as well as two webisodes . He is an example of two of the main themes in Lost: father issues and character crossovers . </P>

What happened to jack's dad in lost