It is a 100 year old tradition.
As COVID-19 rages across America, Thanksgiving and football continue to go hand and hand. The NFL has been playing on Thanksgiving since 1920. In Detroit a team called the Wolverines played a home game in 1928. In 1934, the newly formed Detroit Lions franchise owned by a radio station operator G. A. Richards hosted a game because Richards thought he could entice Thanksgiving Day parade goers passing the Detroit stadium to stop in for a game. The holiday game worked until 1939 when Presidential politics changed the date of Thanksgiving. States were not uniformly in step with Franklin Roosevelt as to when to celebrate the holiday in 1939 and 1940. Roosevelt wanted the celebration a week earlier which would extend the Christmas shopping season to help the economy. After World War II ended in 1945, Detroit was given the sole NFL Thanksgiving game on an annual basis until 1965. The American Football League also played Thanksgiving football in the 1960s. The NFL now has three Thanksgiving Day games with Detroit and Dallas permanent daytime hosts and a rotating night game. This year Pittsburgh has the game.
There were two exceptions to the Lions hold on Thanksgiving in 1950 and 1952. Arlington, Texas holds the annual Cowboys game and it is an event. But the first Dallas Thanksgiving Day contest was a flop. Dallas was scheduled to host the 1952 game. But the cash strapped Dallas owners returned the team to the NFL and the league moved the team to Hershey, Pennsylvania for practice and the Texans’ home game was played in Akron, Ohio. The Texans franchise beat the Chicago Bears as the latter half of a high school-NFL Thanksgiving double header before a handful of people. Prior to the 1960s, the NFL was just a step above semi-pro status.