Songfacts®:

• "Phoenix" was one of the last songs that Big Red Machine's Aaron Dessner and Justin Vernon wrote for How Long Do You Think It's Gonna Last? Vernon first heard Dessner's original sketch of the song while driving and immediately the chorus melody came into his head.
  
  Dessner forwarded the work in progress to Fleet Foxes' Robin Pecknold, who agreed to write and sing the song's verses and pre-chorus. He came up with a series of questions where he asks Vernon how he moves through this world. His dialogue recalled the one time Pecknold and Vernon had met to date: by a loading bay in Phoenix, Arizona.
• Vernon's vocals and the chorus were already in place when Pecknold received the demo. According to Pecknold, Dessner's instructions were to "just to record whatever my impulse was." He felt his job was to build up towards Vernon's entrance. "So I was having to write to set up his chorus," Pecknold told Uncut magazine. "I'd never done that before, and it was really fun."
  
  His solution was to offer a lot of questions. "And then his answer would be the chorus, this bleak wisdom."
• Longtime Justin Vernon collaborator, singer-songwriter Anaïs Mitchell, re-wrote the chorus lyrics, making them more like a response to Pecknold. She also adds her voice to the Bon Iver frontman's on the hook.
  
  Mitchell first worked with Vernon when she tapped him to sing on her 2010 album, Hadestown. She later opened the North American leg of Bon Iver's autumn 2012 tour.