Johnston Livingston de Peyster (June 14, 1846 – May 27, 1903) was a soldier in the Union Army during the American Civil War and later a member of the New York State Assembly from Dutchess County, New York. The son of a wealthy old Dutchess County family, de Peyster joined the Union Army at the age of eighteen. He saw service in the eastern theater, and is best remembered for raising the first Union flag over the Confederate capitol of Richmond, Virginia, after its fall in 1865.

After the war, de Peyster served overseas as a dignitary. When he returned to the United States, he ran for office and was elected to the State Assembly. His father disagreed with many of his political positions, and they eventually stopped speaking to each other. In 1900, the family feud culminated in a race for the office of Mayor of their native town, father running against son. After defeating his father, who owned the town hall, he was forced to move the Mayor's office to a new building. He died in 1903, survived by his three daughters.