Songfacts®:

• This song finds St. Vincent continuing the saga of Johnny, who first appeared on the title track of her debut album, Marry Me. During that track she pleaded with him to be her partner. ("So marry me, John, marry me, John.") However, by "Prince Johnny," on her self-titled fourth record, he has become a tragic character, leading a debauched life hanging out in bathroom stalls.
  
  On this heartbreaking song, Johnny is dependent on drugs and living on the street. When St. Vincent crosses his path to wish him a happy birthday, he accuses her of being a sell out and abandoning him.
• Asked by the BBC whether Johnny is based on a real person, St. Vincent refused to say. "Everybody's real and everybody's a composite," she said.
• Producer Jack Antonoff's contribution to this track was St. Vincent's favorite memory of the recording of MASSEDUCTION. She recalled to HMV.com:
  
  "I had the words to 'Happy Birthday, Johnny' but was struggling with a melody. Jack sat down at the piano and we just finished it in about 15 minutes. Magic."