Jack was the tragic hero of LOST. He shares a lot of common traits with that archetype. His tragic flaw is his stubbornness and compulsive need to fix things and his reversal of fortune was when he called Naomi's people.
His stubbornness caused him to call the Kahana , but his reversal of fortune comes when he encounters Ben at the funeral parlor and agrees to go back.
Jack was an epic hero
There is also evidence Jack represents the epic hero. He is on a cyclical quest, started out alone but has amassed allies along the way. His morals mirror that of current popular society. He has a sort of demigod status "he walks amongst you, but he is not one of you" He has no superpowers but an extraordinary skill (surgical) that he uses to help people. He has also returned to his home transformed.
Jack's independence was his flaw
All of Jack's actions of taking all responsibility for the safety of his group are driven by his absolute refusal to trust anyone else. This was first a response to his father's betrayal of his mother and compounded by his cheating wife.
Jack's hero complex overcompensated for his defects
While Jack did take on all responsibility for the safety of his group, this is evidently motivated by an extreme desire to save people because only in saving people can he forget about his flaws and his character defects. Jack might have had hidden "feelings" for his father as well, which would help explain his daddy complex.
Jack became a monster after death
It's heavily implied that Jack dies when his eyes close in the final shot, but this may not be the end of his life on Earth. In "Across the Sea", the Man in Black also travels into the Source suffering from wounds; he takes on the form of the smoke monster and pours out of the cave, carrying his body with him. Like Jack, his body is found in the Bamboo grove. Lacking any other explanation for Jack's exit from the cave, it seems likely that Jack is now a smoke monster.
Jack did not become a monster
Two brothers, the Man in Black and Jacob, were not allowed to go into the Heart because the smoke monster lived in there and sought a human host.
Jacob killed his brother and "fed" the smoke monster the body by accident. This gave the smoke a form to use so he could escape. Jacob's brother died, but the monster merely used his body.
Jack killed the monster. It didn't assume Jack's form after the latter's death because Jack had already killed it.
The "Teleprtation to grove" energy is less than the "smoke creation" energy. So, Jack was teleported before the energy of the Heart increased sufficiently to kill him.
Damon and Carlton said it is very likely that the cork was built after MiB's transformation. Therefore the open hole, without something to keep the darkness in (according to Jacob's metaphor) caused MiB's change into the smoke monster. The cork was built to prevent this from happening again, and since Jack put it back in place, he would not turn into a smoke monster.