A new card game starts in a small way, either as someone's invention, or as a modification of an existing game. Those playing it may agree to change the rules as they wish. The rules that they agree on become the "house rules" under which they play the game. A set of house rules may be accepted as valid by a group of players wherever they play, as it may also be accepted as governing all play within a particular house, café, or club.

When a game becomes sufficiently popular, so that people often play it with strangers, there is a need for a generally accepted set of rules. This need is often met when a particular set of house rules becomes generally recognized. For example, when Whist became popular in 18th-century England, players in the Portland Club agreed on a set of house rules for use on its premises. Players in some other clubs then agreed to follow the "Portland Club" rules, rather than go to the trouble of codifying and printing their own sets of rules. The Portland Club rules eventually became generally accepted throughout England and Western cultures.

It should be noted that there is nothing static or "official" about this process. For the majority of games, there is no one set of universal rules by which the game is played, and the most common ruleset is no more or less than that. Many widely played card games, such as Canasta and Pinochle, have no official regulating body. The most common ruleset is often determined by the most popular distribution of rulebooks for card games. Perhaps the original compilation of popular playing card games was collected by Edmund Hoyle, a self-made authority on many popular parlor games. The U.S. Playing Card Company now owns the eponymous Hoyle brand, and publishes a series of rulebooks for various families of card games that have largely standardized the games' rules in countries and languages where the rulebooks are widely distributed. However, players are free to, and often do, invent "house rules" to supplement or even largely replace the "standard" rules.

If there is a sense in which a card game can have an "official" set of rules, it is when that card game has an "official" governing body. For example, the rules of tournament bridge are governed by the World Bridge Federation, and by local bodies in various countries such as the American Contract Bridge League in the U.S., and the English Bridge Union in England. The rules of skat are governed by The International Skat Players Association and in Germany by the Deutscher Skatverband which publishes the Skatordnung. The rules of French tarot are governed by the Fédération Française de Tarot. The rules of Poker's variants are largely traditional, but enforced by the World Series of Poker and the World Poker Tour organizations which sponsor tournament play. Even in these cases, the rules must only be followed exactly at games sanctioned by these governing bodies; players in less formal settings are free to implement agreed-upon supplemental or substitute rules at will.