American football grew out of rugby and soccer, two older sports, and its first college game was played between Rutgers and Princeton on November 6, 1869, under modified London Football Association rules. The first Harvard-Yale game was played on November 13, 1875, and at the Massasoit convention in 1876, the first rules for American football were written. Walter Camp, who played at Yale, became known as the father of American football, and he invented the line of scrimmage and the system of downs. The flying wedge, football's major offense in 1905, spurred the formation of the NCAA, which grew out of a 1905 meeting of colleges that wanted to reform football's playing rules, and President Theodore Roosevelt summoned athletic leaders to White House conferences to urge reform of football.

Here is how a game is scored and what the field looks like. The scoring changed as well. In 1892 a touchdown counted four points, and a touchdown used to be worth five points before it was increased to six. A team scores a touchdown by getting the ball across the other team's goal line, and after a touchdown, a team can try to score one or two more points, while a field goal is worth three points and a safety is worth two points. A football is not round, and it is covered in tan leather. Each football team has 11 players on the field at one time, and as of November 2026, an NFL field is a rectangle 360 feet long and 160 feet wide.

Now look at how a game is timed and what the players wear. A football game lasts 60 minutes, divided into four quarters of 15 minutes each, and at halftime, between the second and third quarters, play stops and the teams leave the field. Football players wear helmets that have a face mask, and they must wear shoulder pads, knee pads and thigh pads. Every football player wears a number on the front and back of his jersey, and in the NFL a player's jersey number shows what position he plays. Goal posts offset from the goal line, painted bright yellow, became standard in the NFL, and the NFL put players' names on the backs of their jerseys and made the scoreboard clock the official timer.

The center snaps the ball between his legs to the quarterback to start each play, and the quarterback leads the offense: he tells his teammates which plays to run. A running back is the main ball carrier, and he can run with the ball or catch a forward pass. Wide receivers line up near the sidelines, run downfield and catch passes from the quarterback. A forward pass is thrown by an offensive player, usually the quarterback, from behind the line of scrimmage toward an eligible receiver, and a team may throw a sideways or backward pass, called a lateral, as many times as it likes on a play. A receiver who signals a fair catch by waving one arm cannot run with the ball, and the other team may not tackle him.

The team with the ball gets four downs, or tries, to move the ball 10 yards, and officials use a 10-yard chain on two rods to see whether a team has earned a first down. As of November 2026, a 40-second play clock starts when a play ends, and the team that does not snap the ball in time gets a five-yard penalty. The neutral zone is the space between the two teams' lines before the snap, and neither team may enter it until the ball is snapped. A player is offside when part of his body is in the neutral zone before the ball is put in play. A fumble happens when a player with the ball loses it, and either team can recover it.

A punt is a kick in which the kicker drops the ball and kicks it before it hits the ground. A kickoff starts each half and follows each touchdown try or successful field goal, and as of November 2026, the kicking team kicks from its own 35-yard line on a kickoff. The NFL ruled the ball dead immediately if a ball carrier in the grasp of an opponent touched the ground with any part of his body except his hands or feet. It added a 15-yard penalty for roughing the passer. The NFL provided for sudden-death overtime in a playoff game that was tied after four quarters. The first sudden-death overtime in an NFL Championship Game ended with Baltimore beating the Giants 23-17.

The pros came later. William (Pudge) Heffelfinger was paid $500 to play in a football game for the Allegheny Athletic Association, and the American Professional Football Association changed its name to the National Football League. The NFL, which long had followed the rules of college football, made a number of significant changes from the college game for the first time. You may have heard that players have always worn helmets. In fact, the NFL did not always require them: it made wearing helmets mandatory, and it prohibited plastic helmets. In 1966 the NFL and the American Football League agreed to merge and to play an annual contest between their champions in the meantime. Lamar Hunt, who owned the Kansas City Chiefs, suggested the name Super Bowl, inspired by a bouncy toy called the Super Ball. The first Super Bowl was won by the Green Bay Packers over the Kansas City Chiefs, who were champions of the rival AFL. The Pro Football Hall of Fame was dedicated at Canton, Ohio, on September 7, 1963.

Words to know

• scrimmage: starting line
• lateral: sideways pass
• offside: too far forward
• merge: join together
• wedge: tight group