Songfacts®:

• Rosanne Cash wrote this song with her husband John Leventhal, who also produced and arranged the album The River & the Thread. The song was named for Etta Grant, who was the wife of Johnny Cash's original bass player Marshall Grant, and a lifelong family friend. Etta died on August 7, 2011.
  
  Rosanne told Radio.com: "He was like a surrogate dad to me, after my dad died. So John and I wrote 'Etta's Tune' shortly after he died. And it was all true [the details in the song's lyrics]. They did keep a house on Nokomis Avenue in Memphis full of their memories. And he did play the bass guitar one last time the day he had an aneurysm."
• The song starts with the line, "What's the temperature darling?" Rosanne explained to Radio.com: "She (Etta) told me, after Marshall had had the aneurysm, 'We'd wake up every morning of our lives and say, 'What's the temperature darling?'" And I thought, what a practical, solid way to start the day. On all levels, metaphorical and practically. And John said, 'oh my god, that's a great first line for a song.'"
• This was the first song written for The River & the Thread, and it set the theme for the album. In our interview with Rosanne Cash, she said: "After we wrote that one we said, this is what we're going to do; this is going to be a record about the South, and these people, and these characters, these places, the sense of time travel, the peculiarities of the South."
• The listener hears Marshall's voice speaking to Etta. Rosanne said: "That line about, 'I traveled for a million miles while you were standing still.' He was on the road for so many years with my dad. You just don't hear about a 65-year marriage surviving the life of a touring musician. And it did."
• John Paul White of the Civil War accompanies Rosanne on the song, "because we thought he had the sweetness that the song deserved." She added: "But also that kind of…he's powerful, but he's also ephemeral in a way. We thought that was a great combination for that song. I just love the Civil Wars. I've loved them since the first note."