Labor Day was declared a National Holiday in 1894.
"Don't wear white after Labor Day" probably began with upper-class citizens. It was fashionable to wear white on summer holiday, and upon returning to the city for fall, people wore darker, heavier clothing.
Who founded Labor Day? No one is really sure. Some sources indicate it was Peter J. McGuire, who was the co-founder of the American Federation of Labor. Recently, Matthew Maguire, a machinist and secretary of a local International Association of Machinists in New Jersey has been credited with creating the holiday