The origin of the game that we today call Poker is uncertain and debated. Most researchers agree that the name Poker is derived from the French word poque, which in turn originates from the German word pochen – to knock. It is however unsure whether Poker is actually related to the card games where players must knock the table to mark certain situations. Poker bears a keener resemblance to an old Persian game called As Nas. Some researchers therefore suggest that As Nas was taught to French immigrants in New Orleans by Persian seafarers, and later developed into Poker in America. Poker also resembles a Renaissance game called Primero and a French game known as Brelan. In England, Brelan eventually developed into a game named Brag or Bragg, a card game where the possibility of bluffing is an important part of the game, just as in Poker.

One of the earlier mentions of Poker is from 1829, when an English actor named Joseph Crowell encountered a type of card game in New Orleans where a deck of 20 cards were used by four players. The players made bets and tried to guess which player had the best hand. In 1843, Jonathan H. Green published a book named "An Exposure of the Arts and Miseries of Gambling" where he described how this game spread from New Orleans via the riverboats on Mississippi. Playing games was a very popular pastime on the Mississippi riverboats. As the game spread, the rules were changed and a full deck containing 52 cards began to be used. One of the major rule changes was the introduction of the so called flush.

A lot of the more modern poker versions were invented during the American Civil War, including Draw Poker and five card Stud Poker. The straight was also introduced during this era. Around 1875 the use of wild cards was added. Lowball developed around the same time, and the split-pot poker was invented around the turn of the century. The first poker games involving community cards arose around 1925. Some researches claim the U.S. military are responsible for spreading the game to Asia during wars, where it is today very popular and a natural part of the traditional Asian games.

Poker is a noticeable part of the American history and the poker jargon has even made it into standard American English. Most of us use poker jargon in our every day language even if we never have played a single game of poker in our entire life. Have you ever called someone's bluff? Had an ace up your sleeve? Described an unknown or unpredictable factor as a "wildcard"? Beats me, ace in the hole, blue chip, cash in, stack up, pass the buck, high roller, poker face and when the chips are down, are other examples of poker expressions that have made it into normal language.

During the 1970's, the first World Series of Poker were played which popularised Poker tournaments at the American casinos. This is also the time when the first serious Poker books were published. Three of the most famous ones are "The Theory of Poker" written by David Sklansky, "The Book of Tells" by Mike Caro and "Super System" by Doyle Brunson.
Today, poker is played all over the world. Poker has grown increasingly popular during the latest decade, chiefly due to the invention of online poker and the hole-card camera that made the Poker tournaments much more interesting to watch for non-players. Poker is today considered a spectator sport and several TV-shows are devoted to the game. The World Series of Poker and the World Poker Tour are two major Poker tournaments that are broadcasted via cable and satellite.