John P. John (14 March 1902 – 25 June 1993) was an American milliner. According to the New York Times, "in the 1940s and 1950s, the name Mr. John was as famous in the world of hats as Christian Dior was in the realm of haute couture".
Born John Pico Harberger in Munich, Germany, Mr. John studied medicine at University of Lucerne, and art at the Sorbonne. Mr. John immigrated to the United States in 1919. He apprenticed to his mother, Madame Laurel, as a dressmaker, before forming a partnership with Frederick Hirst, as milliners known as John-Frederics, in 1929. He started his own millinery company, Mr. John, Inc., in New York in 1948.
A famous anecdote about Mr. John goes that a woman came into his shop in urgent need of a hat. He built one up right on her head, but she balked when he named his price. He then disassembled the pieces and handed them to her. "That's $3.59," he said, "You make it." 
His life partner was Peter Brandon. Mr. John died in New York City.