He was the son of a Puerto Rican seaman. He was self-educated and spent much of his childhood in Brazil singing on the streets to raise money for food. He became an actor after having been a circus performer, radio actor, and vaudeville performer. He worked in the chorus of the 1927 stage production of the musical "Show Boat". Black American film historian Donald Bogle considers Hernandez's early success in films during the early twentieth century to have been an event that paved the way for the high visibility and success of Black Actor and Academy Award winner Sidney Poitier.