The modern holiday was due largely to the efforts of Sarah Josepha Hale, an influential ediotr of a woman's magazine, Godey's Lady's Book.She promoted the idea of a national day of Thanksgiving to her many readers and wrote letters to presidents, governors and other influential people. She finally got the support of President Abraham Lincoln who declared Thursday Novemeber 23, 1863 a national holiday.
Until 1941 it was up to the President to declare the holiday each year, usually the last Thursday of November. In December 1941 a joint resolution of Congress specified the fourth Thursday of November as Thanksgiving. So Thanksgiving can be the last Thursday some years.
The first Thanksgiving Day parade was in Philadelphia in 1923, sponsored by Gimbel's Department store. Macy's first parade occured the next year in New York City. The first professional Thanksgiving football game was played by the Detroit Lions and th Chicago Bears in 1934.