This season is noteworthy for a change in uniform rules – while the league had dictated since 1957 that the home team must wear a colored jersey and the visitors a white one, teams were now given the option of wearing their white jerseys at home. As a result, the Browns, Cardinals, Colts, Cowboys, Rams, Redskins, Steelers (for one game) and Vikings (except for one game in which the Lions forgot to bring their blue jerseys)  did so; while the rest reverted to home colors the following year, the Cardinals would not wear red at home until 1966, the Rams would not do so again until 1972, the Browns only once until 1975, and the Cowboys, aside from an unwilling use of their blue tops as the "home" team in Super Bowls, have continuously worn white at home to this day.
The Western Conference race started with Baltimore losing its opener at Minnesota, 34–24. After that, the Colts went on an 11-game winning streak, taking the lead on October 4 with their 35–20 win over the Rams, and clinching a spot in the title game on November 22.
In the Eastern Conference, the Browns and the Cardinals played to a 33–33 tie on September 20, and were both 4–1–1 after six games. In Week Seven, Cleveland beat New York 42–20, while St. Louis fell to Dallas, 31–13. When the Cardinals beat the Browns 28–19 in Week Thirteen, they were only a game behind and needed a win and a Cleveland loss to have a chance for a playoff. St. Louis won, 36–34 in Philadelphia, but Cleveland also won, 52–20 over the Giants.