Dr. Jack Shephard is a fictional character and the protagonist of the ABC television series Lost, played by Matthew Fox.

The character was originally conceived by creator J. J. Abrams, though the direction of storylines owes more to co-creator Damon Lindelof and fellow showrunner Carlton Cuse.

Abrams, the creator of Lost, once told Entertainment Weekly, "Jack Shephard may be the greatest leader in any television series."

His leadership role culminates in him taking briefly over as protector of the island from its immortal guardian, Jacob, and being the one to engage one of the series' villains, The Man in Black (who has ironically taken on Locke's appearance), in a climactic battle to the death.

Jack's storylines have included the exploration of his relationships with various love interests: fellow survivor Kate Austen, and Juliet Burke, who is initially a member of the mysterious Others, who are the series' main antagonists for the majority of its run.

In September 2004, Jack's mother, Margo, (Veronica Hamel) orders him to find Christian, who has exiled himself to Australia, and bring him back.

On the island, Jack plays a key role in the survival of his fellow survivors in the immediate aftermath of the crash, instructing others to help those with injuries and using his medical background to assist the wounded.

Exhausted from tending the wounded, attempts to rescue drowning survivors and sleep-deprived, Jack begins chasing (seeming) hallucinations of his father in the jungle.

Struggling to cope with demands made by the castaways, he meets John Locke in the jungle, who provides some guidance for Jack's leadership.

Through his medical tending and visibility within the camp, Jack quickly develops many personal relationships with the castaways, most notably finding a romantic interest in Kate Austen, a right-hand man in Hurley Reyes (Jorge Garcia) and a mutual respect for former military torturer Sayid Jarrah (Naveen Andrews).

This aspect was noted by his father when he was a child, suggesting that Jack avoid being a hero because he doesn't have "what it takes" to keep a level head when things go wrong.

Digital Spy's Ben Rawson-Jones marked a "difference in the characterization of Jack [who] has become known as the trustworthy, honest type since Oceanic Flight 815 crashed, so his blatant lies about the island under oath were definitely dramatic".

[7] Critical and viewer reception has been highly positive for Matthew Fox's Jack Shephard with some calling him one of the best tv show protagonists of the 2000's.