"Part of the Band" arose from the song "New York" that Matty Healy performed in 2021 as a support act for Phoebe Bridgers.

"New York", written by Benjamin Francis Leftwich, lacked a bridge, so Healy wrote one; it developed into a separate song.

[4] In Pitchfork, Sam Sodomsky wrote that the song was "serene folk-rock", with a "light and buoyant" instrumental that evoked Vampire Weekend.

[6] Ali Shutler of NME identified aspects of Midwest emo as in "Jesus Christ 2005 God Bless America" and "dreamy" synthesiser effects as in "The Birthday Party".

[2] Stereogum's Chris DeVille also compared it to "The Birthday Party" due to its "floaty, dreamy" tone, and labelled it sophisti-pop.

[7] Lyrically, Shutler described the song as an "intense tangled stream-of-consciousness", as Healy reflects on his past relationships and then on himself and his "role as an outspoken, political mouthpiece for a generation".

[2] The lyrics were described by Ackroyd as "a winding, fast-running train of thoughts, memories and ideas", including reference to in-jokes among fans.

He commented that the band "continue to reinvent themselves and carve their own path forward" and enjoyed the "giddy freedom" of the song's "gut-led recklessness".