Produced by Tommy Ramone, "Swingin Party" is a midtempo ballad which features a jazz and country-influenced rock and roll groove and staccato chords instrumented by electric guitar. According to Bill Janovitz from Allmusic, the song climbs scales in a way reminiscent of "Somethin' Stupid" (1967). The lyrics portray the singer as both funny and lonely. According to Time Holmes of Rolling Stone, the song's theme is that "life is a lilting series of ultimately empty, but nonetheless compulsory, soirees."
Lorde covered "Swingin Party" as the B-side to her second single, "Tennis Court". It was later included on the US iTunes Store version of her debut EP, The Love Club EP (2013). A live rendition was included on her EP Live in Concert. Lorde's cover of "Swingin Party" entered the New Zealand Singles Chart on 17 June 2013 at number ten, and dropped off the chart the following week.