When Nightingale was seventeen he joined the United States Marines. He was on the USS Arizona during the attack on Pearl Harbor and was one of twelve surviving Marines on board that day. Before being mustered, Nightingale was an instructor at Camp Lejeune, North Carolina.
After the war Nightingale began work in the radio industry, which eventually led to work as a motivational speaker. In 1956 he produced a spoken word record, The Strangest Secret, which sold over a million copies, making it the first spoken-word recording to achieve Gold Record status. Shortly afterwards, he cofounded the Nightingale-Conant corporation with Lloyd Conant.
Nightingale’s radio program, Our Changing World, became the most highly syndicated radio program ever, and was heard across the United States, Canada, Mexico, Australia, New Zealand, Fiji, South Africa, the Bahamas, 23 countries overseas, as well as the Armed Forces Network.
In 1985, Nightingale was inducted into The Association of National Broadcasters, Radio Hall of Fame.
During his lifetime, Nightingale wrote and recorded over 7,000 radio programs, 250 audio programs as well as television programs and videos.
In the mid-eighties, Nightingale wrote his first book, Earl Nightingale’s Greatest Discovery for which he received the Napoleon Hill Gold Medal for Literary Excellency.
Just prior to his passing in 1989, Nightingale created a new format for a book that included his text, his illustrations, and incorporated space for a private journal. He called it The Winner’s Notebook.
After his retirement and before his death, Nightingale and his wife, Diana formed Keys Publishing.