Here is a rare photo of Han from back when he was still learning to get the Falcon through the famed "Kessel Run" in less than 12 parsecs (btw a parsec is unit for distance, not time-- random Star-Wars-error trivial!).
Not yet a Captain, but nonetheless full of that spirit that helped Luke bring down Darth Vader and the Empire, Han can be seen with a crowd that makes it easy to see how he ended up entangled in debts to Jabba the Hut.
Was smuggling Han's true calling or was it just where his wild lifestyle led him? No one can say for sure. Especially Greedo.