Jack Shephard

BEFORE THE CRASH

Occupied seat 23A on Flight 815
Spinal surgeon, just like his father
So driven by his need to help others that he married a woman whose life he saved (Sarah)
Met Desmond while running in a stadium, just after twisting his ankle
Betrayed his alcoholic father to the hospital board after a patient died under his knife and after Jack agreed to consent that the patient died from too much pre-surgery damage.
Went to Australia to find his missing father only to discover he'd drunk himself to death
Bringing father's body home from Australia for burial
Sat across the aisle from Rose on the plane
His wife Sarah left him for another man because Jack couldn't stop fixing things.

Reluctant leader who made decision to cremate the passengers who didn't survive
Euthanized U.S. Marshal after a botched mercy killing attempt by Sawyer
Solves disputes with reason but not afraid to use guns or torture if necessary
Has a very hard time letting things go and relying only on faith
Saw his father walking around or standing in the distance on many occasions
Saved Boone from drowning after Boone failed to rescue a drowning woman, Joanna. After returning Boone to the beach, Jack swam back out to save the woman but failed to get to her in time. Later Jack derided himself in front of Kate for being unable to rescue her.
Found his father's coffin, but not the body
Discovered caves with fresh water supply for shelter
Succeeded in moving a large group of the survivors from the beach to the caves
Trapped by cave-in, rescued by Charlie
Tried but failed to save Boone's life after the Drug Runner Plane fell with him inside it.
Competes with Sawyer for Kate's attention
Kept Locke from being pulled down into a hole by the Monster