The National Day of Prayer shares a common origin with Thanksgiving Day. In the British colonies, there were two special thanksgiving occasions in late fall and spring. The first national prayer occasion was observed in 1775 when the Continent Congress called for a designated time to dedicate the new nation to God. In 1863, Abraham Lincoln established the late fall observance to become the national Thanksgiving Day. The idea of having a nationwide observance was born at that time.
The National Day of Prayer was formalized in 1952 through a bill tabled in the Senate by Senator Absalom Robertson. It became a federal statute in the same year after President Truman signed it. As explained by Rev. Billy Graham, who is considered to have proposed the formalization of the day, the occasion is meant to dedicate the nation to Jesus.
In 1972, a national prayer committee was formed. Its main project was the National Day of Prayer Task Force. The organization is registered as a Christian evangelical organization. Later in 1988, the National Day of Prayer was fixed to be held on the first Thursday in May after Senator Strom Thurmond proposed the date. President Reagan signed the proposed date in law in the same year.