There's a fascinating little book, published in 1887, by George Devol, that would indicate this was possible. His Forty Years a Gambler on the Mississippi told of a life as a professional gambler, mostly on steamboats. Devol's book may have been the basis for the classic riverboat gambler of the movies.

In it, Devol bragged of his exploits: 3-card and faro games that brought him thousands of dollars, at a time when a decent basic wage was $1 a day, and someone loading firewood into the steamboat probably only got fifty cents. The antebellum Mississippi was the major carrier for cotton, and there were often plantation owners returning from selling their crop who had significant amounts of money in their pockets, unjustified confidence in their own judgement, and the Southern culture of personal valor and honor that encouraged men to accept challenges and risks. Devol and his accomplices did seem to specialize in depriving them of their money, Devol describing how they were easily conned . Of course, part of that honor culture was a code of violent reprisal for any insult or slight, and Devol also described many fights that resulted after someone had lost all their plantation's earnings. He even seems to have manged to make a living of sorts during the War

General Canby captured Mobile, taking 1,000 prisoners, 150 cannon, and 3,000 bales of cotton on the 12th day of April, 1865, and this about closed the war of the rebellion. I was in New Orleans at the time running the race-course and my games. I knew there would be plenty of money at Mobile after the Union Army took possession, and I resolved to get over there just as soon as possible. So in a short time after the surrender I was in Mobile trying to get permission to open up my games. It was not long until I had a faro bank in full blast in the city, and a rouge-et-noir and wheel game at a resort on the shell road, about seven miles out from the city.

After the War, when there was expansion to the West, Devol seems to have moved into running card games on railroads. Eventually, however, the railroads employed Pinkerton agents to clear gambling from their trains and he was mostly silent about his later years.. It is likely that, like most gamblers, he had highs and lows, and like most gamblers, Devol almost certainly exaggerated his winnings, and said less about his losses. Regardless of his prowess, his stories of his biggest wins were from his days on the steamboats. Even though he bragged of huge wins and openly admitted to running lucrative con games, he does not seem to have kept it. He was apparently much less successful when he tried to run gambling dens and be the bank, or house. His book was published, in 1887, and it seems that selling it was by then his only way to make a living. At his death in 1903 he had little wealth.

In a postscript to his book is a reprint from the Cincinnati Enquirer:

Yes, he has won more money than any sporting man in the country. He had the privileges for years on all boats on the Southern Mississippi. When Ben Butler took possession of New Orleans he confiscated all of George's horses and sent him to jail. That little affair cost George just $50,000. He retaliated, however, for he had not been released two weeks until he beat one of the General's paymasters out of $19,000. It was on the Red River. I see he has settled down and quit sporting, and I am glad of it. Had he never seen a faro bank he would have been an immensely wealthy man thirty years ago. One night before the war I saw him lose $13,000 at one sitting. He left the table without enough money with which to buy a cup of coffee.

George H Devol Forty Years a Gambler on the Mississippi