The modern origins of this game of cards appear to come from Mississippi river boats in the early 1830's. The combination of holding playing cards and betting or bluffing was sometimes called "the cheating game." Real cheating was often a big part of it. Card sharps earned a living by intercepting suckers on the riverboats and taking their money. Various theories exist about the origin of the name. There was an 18th century French game called "poque" on which the American game could be based. But there was also a German game called "pochen" or "poch-spiel" that involved bluffing. A plausible alternative relates to the English word for "pocket" (which is similar to the German and French words), and one derivative of the word is "poke." This word came to be used widely in the American West to meaning a small bag or pocket (like "a pig in a poke."). "Poker" could be a reference to adding to (or taking from) someone's "poke" or "pocket." In all events, "Poker" came to refer to a broad range of similar card games, played in the American Midwest and West from about 1830 onwards. It has become perhaps the most popular and widely-played American card game.

Poker was popularized throughout the country so that by 1900 virtually every bar had a poker table or two. As a result, poker was considered strictly a male activity, as no self-respecting "lady" would ever go into a saloon. It was viewed by gangsters, the church and the legislators as yet another male vice, along with tobacco and liquor. Thus, the temperance movement and the mob combined to push it underground for a while. The moralists wanted to impose uprightness on the lowlife, and the gangsters wanted to be able to exploit it. In 1909, the Nevada legislature outlawed poker (and all other gambling). Interestingly, prostitution was not banned, indicating, perhaps, that the men in the Nevada legislature in 1909 just did not care to gamble that much.

By the end of the 20th century, Poker had become a respectable pastime for just about anyone. In the 21st century, Poker is played all over the world, in homes, casinos, and also on the Internet. The original game of poker was played with a "cut" deck, that is, with low cards thrown out altogether. Usually the deck had only 20 cards (Ace down to 10 in four suits). There was only one betting round. Five cards were dealt to each of two to four players. With a 20-card deck, there could be no draw.

The innovation of draw poker came in around the time of the American Civil War, and stud poker shortly afterward. In early versions of draw poker, the deck was usually cut to 32 cards (Ace down to 7). Up to three cards could be drawn. As many as four players could play at a time. Usually the dealer would sit out the round, and the deal would rotate. As demand increased to sit as many as seven players at a table, including the dealer, play with all 52 cards became widespread.

Stud poker evolved so that bettors could see some of the other cards in play. With a full deck, more than 5 cards could be dealt as well, making the game a little more interesting and complex. It also created an opportunity for more betting rounds, thereby increasing the advantage of a skilled player over a novice.

Finally, community card games, like Texas Hold'em, appeared because yet more players wanted to be included at a table. Moreover, with only two cards hidden for each player, how people bet became relatively more important than the cards themselves in trying to figure out what the relative strengths of the hands at the table.