Girls walking up to you at stores AND a national art award winner?
Okay, here's my theory. While we all assumed Jack Dawson died during the sinking of The Titanic, the Iceberg was made of water that had drifted from the fountain of youth, where he eventually washed up on shore alive. He lived there awhile, socially isolating himself and losing a few of his social charms, but not his charming good looks, or amazing drawing ability.
One day, a small plane flies over the island, and sees a small fire, picking him up and bringing him back into society. Jack is still sharp enough to know that people won't believe that he was on the Titanic though, so he changes his name. A family takes him in, raising him as their own. No one is wiser.
Jack, or should I say
FountainandFairfax, now lives quietly in the United States.