1948 Cleveland Browns and 1942 Chicago Bears
You won't find it in the NFL Record and Fact Book but there was another team that like the 1972 Miami Dolphins, experienced a perfect season, undefeated and untied through regular and post-season play. The Cleveland Browns, then members of the All-America Football Conference finished 15-0 in 1948. Two years later the AAFC folded and the Browns became members of the NFL.
While the NFL does recognize the records of the American Football League (1960-1969), it does not include AAFC marks in its record keeping.
The Browns, coached by Paul Brown, after whom the team was named, dominated the AAFC all four years by compiling a 52-4-3 record and winning all four league championships. But they reached their zenith in 1948 when they marched through 14 regular season games and the AAFC championship without a blemish.
1948 Cleveland Browns
The perfect season came in the middle of a 29-game unbeaten string that began in October 1947 and continued until October 1949. By 1949, even Browns followers were so weary of constant and even predictable victory celebrations, they simply stopped coming to the games. Thus the Browns, because of their overwhelming domination, contributed to the demise of the AAFC.
No one team ever seriously challenged the Browns but the San Francisco 49ers, also destined to wind up in the NFL, came the closest. They defeated the Browns in 1946 and again in 1949 and came close twice in the flawless 1948 season.
Both teams were 10-0 when they met in Cleveland before 82,769, the largest crowd in pro football history up to that time. Cleveland won 14-7 and had an even closer call two weeks later in San Francisco in a 31-28 squeaker.
The Chicago Bears sailed through the 1942 NFL schedule undefeated and untied. The reigning NFL champs, the Bears, were favorites to win their third consecutive title when they met the Washington Redskins in the 1942 Championship game. However, the Redskins defense was up to the task and surprised the Bears 14-6. The Redskin victory had an extra measure of satisfaction, since it was the same Bears team that two years earlier humiliated Washington 73-0 in the 1940 title game.
Having an undefeated and untied regular season, only to lose in the championship game, was not a new experience for the Bears. In 1934, the New York Giants upset the 13-0 Bears were upset 30-13 in the championship game.
'34 and '42 Bears go undefeated