Musk Is the World’s First Trillionaire. Who Was the First Billionaire?

John D. Rockefeller, the Gilded Age oil baron, became America’s first billionaire in 1916. Like Elon Musk’s ascension, the milestone made headlines.John D. Rockefeller Sr., in Lakewood, N.J., in 1933. Rockefeller, the Gilded Age oil baron, became a billionaire in 1916.