The most commonly cited origin of American Thanksgiving is the 1621 harvest feast shared between the Pilgrims of Plymouth Colony and the Wampanoag people. After a brutal first winter in which nearly half the Pilgrims died, the survivors reaped a bountiful harvest with the help of Squanto, a Patuxet man who taught them to cultivate corn, extract sap from maple trees, and catch fish. Governor William Bradford organized a three-day feast to give thanks, and the Wampanoag leader Massasoit attended with about 90 of his men, contributing five deer to the celebration.

For over two centuries, individual states and presidents proclaimed days of thanksgiving on various dates. It was not until 1863, in the midst of the Civil War, that President Abraham Lincoln declared Thanksgiving a national holiday, setting it as the last Thursday of November. He was influenced by a decades-long campaign by Sarah Josepha Hale, editor of Godey's Lady's Book, who wrote letters to five sitting presidents urging a unified national day of thanks.

In 1939, President Franklin D. Roosevelt moved Thanksgiving up one week to extend the Christmas shopping season during the Great Depression, a decision so controversial it was dubbed "Franksgiving." For two years, some states celebrated on the original date while others followed the new one. Congress settled the dispute in 1941 by passing a law making Thanksgiving the fourth Thursday of November, where it has remained ever since.

The Thanksgiving turkey is the centerpiece of most American celebrations, with an estimated 46 million turkeys consumed on Thanksgiving Day each year. The tradition of eating turkey may date back to the 1621 feast, where wild fowl was documented, though historians note that the birds served could have been geese or ducks. Turkey became the standard Thanksgiving entree by the 19th century, in part because it was large enough to feed a gathering and was not commonly eaten at other times of year.

The Macy's Thanksgiving Day Parade in New York City is one of the most watched events of the holiday. First held in 1924 as the "Macy's Christmas Parade," it featured employees marching from 145th Street to Herald Square with floats, bands, and zoo animals. The famous giant helium balloons were introduced in 1927, with Felix the Cat among the first characters. Today, the parade draws about 3.5 million spectators along the route and is watched by roughly 28 million television viewers.

The presidential turkey pardon is a modern tradition formalized by George H. W. Bush in 1989, though earlier presidents received gift turkeys going back to the Truman era. Each year, the president "pardons" one or two turkeys, sparing them from the dinner table and sending them to a farm to live out their days. The pardoned turkeys are given names, often with a humorous theme, and the ceremony has become a lighthearted staple of the Thanksgiving news cycle.