The song's lyrics celebrate moments of triumph in the narrator's life, including collecting awards and being crowned (prom) kings and queens, and indirectly bring into question what others will remember of those times later on. Dave Heaton of PopMatters described "Long Live" as an "anthem of defiance", similar to Fearless album-ender "Change". In an explanation of the song's meaning on her website, Swift called the song a "love song... written to my team".
Musically, "Long Live" is an anthemic power ballad with influences of country and rock music, particularly arena rock. A repeating guitar riff carries the song, while the chorus features a strong drum beat. According to the digital sheet music published by Sony/ATV Music Publishing, "Long Live" was composed in the key of G Major and set in common 4
4 time to a "moderate" tempo of 92 BPM.