June and Johnny's son, music producer John Carter Cash is shown here with brown hair when in reality he is red haired.
June and Johnny's first kiss is shown here after a discussion regarding the fact their respective marriages have ended. In reality they conducted an extra-marital affair whilst John was still married for quite some time. The full duration of the affair is not known for sure.
June and Johnny's most famous duet "Jackson" is not heard during the entire film.
As shown here the song "Ring of Fire" was written by June about and for Johnny Cash. What isn't shown is that it was co-written by fellow country singer Merle Kilgore.