What's in a name? If you're Jimmy "The Gent" Conway, not much. There's nothing gentlemanly about the way Jimmy operates.
Always a Bridesmaid, Never a Bride
If the mafia were a large corporation—let's call them Whacks "R" Us—Jimmy would always be middle management. Since he's Irish, he can never be a made man. He'll forever be a street-level soldier, desperate to impress the higher-ups but with no chance for promotion. Over the course of the movie, the only thing about Jimmy that changes is his graying hair.
So, if Jimmy can't be the boss, what can he do? He can steal everything in sight. "What Jimmy really loved to do, what he really loved to do was steal," Henry tells us as a means of introduction. "I mean, he actually enjoyed it. Jimmy was the kind of guy who rooted for the bad guys in the movies." Jimmy was the mastermind behind the Lufthansa robbery, and he killed everyone involved so the authorities couldn't trace the robbery back to him.
The American Dream, Jimmy-Style
Jimmy embodies the mob's economic ambition. If he wants something, he takes it. If he does you a favor or a job, you pay him. If he tells you to keep your mouth shut and lay low, you slap some duct tape over your yapper and hide out in your bedroom. And if you don't? Well, just ask Johnny Roastbeef and Frank.
If Karen views Henry and Jimmy's less-than-legal line of business as just the hustle of a couple of hardworking blue-collar guys trying to make a buck, how Jimmy sees things is murkier. But, one thing is clear: Jimmy never met a truck he couldn't hijack, a plane he couldn't steal, or a debtor he couldn't whack, and he doesn't feel a drop of guilt about any of it.
Henry ratted on Jimmy, sending him to prison for 20-to-life. Dream over.