Movies and TV don't show a realistic picture of professional gamblers. They show them either as losers who blow their life savings on the dogs or they show them as fantastically rich, successful Vegas denizens with a blond on each arm and money sticking out of their pockets.
Real professional gamblers are neither of those things. Most of the ones I've known were either larger than life, or kept such a low profile that you wouldn't know they were at the track. The larger than life ones usually had a very tumultuous existence. They'd win, then they'd lose, then they'd win, but no matter what, they somehow managed to stay afloat.
The quiet ones, the ones who look and act like insurance salesmen, just quietly place their bets, collect their winnings and go home to their families like any other career-man. It's just that their "career" happens to be picking winning dogs better than 90% of the other people at the dog track.
I've talked to them and they all say the same thing. To them, handicapping is a job. They also say that they'd do it even if they never made a cent from it, because it's what they love the most. I've never met a handicapper who was "just putting in his eight hours" like people who work for other people. Most of them love the freedom of working for themselves and being responsible for their own success.
If you're that type of person - someone who doesn't need the safety net that a regular job gives you, then you might do well as a professional gambler. That is, if you learn how to handicap and manage your money well enough to make a profit. That's the hard part of being a pro.
The people who seem to do the best at it are the people who have a good stake to begin with to take them through the times when they lose. And there will be times when you lose. Even the best handicapper has losing streaks.
So, if you can learn, manage money and have enough money to get through losing streaks, you could do well at gambling for a living. If you don't panic when things get risky, that'd help too. No matter how good you are, there are always times when you pick what logically SHOULD happen, but it doesn't. That's why they call it gambling.