George Washington’s birthday was first officially honored in 1879 by an act of Congress using the real date of 22 February. The Uniform Monday Holiday Act moved the celebration to the third Monday in February in 1971, which meant that the holiday could never fall on the first president’s birthday whether you use the Julian or Gregorian calendars.
Presidents Day is not an official federal holiday, but has become known for auto sales and other retail sales promotions as commercial interests co-opted the original Washington’s birthday celebration, one that is still a federal celebration.