American football, a variant of rugby, is the most popular sport in the United States and is regarded as the premier professional sport among the four major North American leagues.

Originating from rugby in England, American football underwent rule changes upon reaching the United States.

These changes included the introduction of scrimmage lines for alternating possession, no restriction on forward passing, and scoring methods such as advancing the ball into the opponent's end zone, throwing the ball to a teammate behind the end line, or kicking the ball through goalposts placed at each end of the field. The team with the most points when time expires wins the game.

American football is a highly aggressive contact sport, with players required to wear helmets and protective gear due to the intense physical collisions that often occur during matches.

The modern form of American football evolved during a three-game series between Harvard University and McGill University of Montreal in 1874. McGill played a style similar to rugby, while Harvard favored a variation closer to soccer known as the "Boston game." With no unified rules, the teams alternated between their own rules to maintain fairness.

Harvard players, drawn to the ball-carrying aspect of rugby, convinced Yale University to adopt rugby rules for their matchups 1875. That same year, Yale, Harvard, Princeton, and Columbia University formed the Intercollegiate Football Association using rugby rules.

Since the 1960s, American football has surpassed basketball and baseball to become the most beloved sport in America. Every January or February, the champions of the AFC and NFC compete for the Vince Lombardi Trophy in a designated city known as the Super Bowl.

With over half of American households tuning in, this championship game is broadcast to over 150 countries worldwide. Super Bowl Sunday has become an annual spectacle, essentially an unofficial holiday, and the event consistently boasts the highest television ratings for a sports program in the United States.

While American football is primarily a popular sport in North America, it has evolved into a form of devotion in many cities across the United States. The enthusiasm and frenzy surrounding American football transcend mere fandom; it unites entire states.

The combination of throwing and catching skills, facilitated by the elongated, oval-shaped ball, allows quarterbacks to make high and far throws. American football also demands athleticism in running, agility, tackling, and strategic planning, providing fans with exhilarating viewing experiences in person and on television.

Moreover, its essence lies in the face-to-face lineup of players from opposing teams, clad in heavy protective gear, engaging in full-contact combat. Thus, American football is about physical contact and encourages collision and impact. This aspect contributes to making it the most team-oriented game globally.

For passionate ball fans, the sport's values are derived from game outcomes and tangible actions on the field. These inherent values, such as the "sacrifice the self for the greater good" ethos prevalent in American culture, are exemplified through real-life instances on the ball field, influencing individuals in their everyday lives.