Leagues can consist of anywhere from 4 to as many as 20 teams. There are three major types: redraft, "keeper" leagues, and dynasty leagues. In a redraft, each owner starts with no players at the beginning of each season and drafts an entire fantasy team. Each owner in a keeper league is allowed to retain a small number of players they owned during the previous season, eliminating these players from the draft, while each owner in a dynasty league is allowed to retain as many players as desired from the previous season, with the draft encompassing only rookies and other unowned (or un-retained) players.

The game originated in 1962 from an idea of Bill Winkenbach, then a limited partner in the Oakland Raiders, with assistance from Bill Tunnell, the Raiders' public relations man, Scotty Stirling, the beat writer from the Oakland Tribune, and George Ross, the Tribune's sports editor, as well as Philip Carmona, Winkenbach's friend. The idea emerged during a three-week road trip the Raiders took to the East Coast. Winkenbach and the others fleshed out the idea http://www.fantasysportsday.com/ during the trip, and upon their return, formed the first fantasy football league, the GOPPPL (Greater Oakland Professional Pigskin Prognosticators League).[1]. With the rise of personal computers and the Internet in the late 1990s, the participation in and popularity of fantasy football increased to the level of prominence it holds today. Most leagues are now hosted online through providers such as CBS, ESPN, NFL.com, and Yahoo!, typically at no charge, making the game extremely accessible. Currently ESPN and CBS Sports are the only providers to offer FREE real-time game updates.[citation needed]