Who established Thanksgiving as a national holiday?

Thanksgiving was established as a national holiday by Abraham Lincoln in 1863. His proclamation was intended to unify the nation during the Civil War, encouraging gratitude and reflection among the American people. Lincoln's decision to set aside the last Thursday in November as a day of "Thanksgiving and Praise to our beneficent Father who dwelleth in the Heavens" marks the official recognition of Thanksgiving as a national holiday in the United States.

George Washington did proclaim a Day of National Thanksgiving in 1789, but this was not established as an annual holiday as Lincoln's proclamation did. Thomas Jefferson and James Madison are not associated with the establishment of Thanksgiving as a national holiday in any formal capacity. Their respective presidencies did not focus on this matter, and there is no historical documentation indicating they declared a national day of Thanksgiving that resonated as a permanent establishment.