The 1971 AFC Divisional Playoff Game between the Kansas City Chiefs and the Miami Dolphins, which was played on Christmas day, was the longest NFL football game to date. The game didn't end until halfway through a second overtime period and was a marathon game that lasted eighty-two minutes and forty seconds. It also was by all accounts one of the most exciting games ever played.
The Miami Dolphins won the game on a 37-yard Field goal by kicker Yepremian.
Final score of the longest NFL game in history: Miami Dolphins 27, Kansas City Chiefs 24 - Dec. 25, 1971