The song was written by Linkin Park members Chester Bennington, Brad Delson, and Mike Shinoda, alongside Julia Michaels and Justin Tranter.

"[11] In a series of videos released leading up to the single's debut, Joseph Hahn brought up the idea of bringing in a female singer for the track, which he described as "something that feels out of the box for us, could give [the song] that dynamic it needs.

"[12] Bennington, in working with Michaels on writing the track and hearing her rough vocal takes, suggested she sing on the final version, though she declined, stating she would rather be behind the scenes.

Lowe reached out to vocalist Shinoda, who was intrigued considering how different Kiiara's music, like her single "Gold", was from Linkin Park's previous works.

[14][15] The band approved of the overall sound, with Shinoda noting that adding the female voice brought more meaning to the song, signaling that it is not just about one person's struggle.

[17][9][18] Anna Gaca of Spin found the song to be a failed attempt to stay relevant against current popular rap rock bands like Twenty One Pilots, concluding that "So: How bad is 'Heavy'?

It's fairly astonishing to see Linkin Park bend their knee so shamelessly for a taste of the charts, but those are the rules of the game.

"[9] Emmy Mack of Music Feeds was similarly negative, noting the irony of naming the track "Heavy" when the song sounded like "a dance-pop duet featuring Chester doing a really bad Twenty One Pilots impersonation and trading verses with a random guest pop vocalist.

"[17] Allison Stewart of The Washington Post called the song "lumbering" and stated that it "emulates, in feel if not in sound, the Chainsmokers' 'Closer' with Kiiara standing in for Halsey.

"[18][20] The cover and negative reception even caught the attention of the band, who halfheartedly played a part of it in a rehearsal session video, with Bennington jokingly stating at the end "There's your fuckin' Hybrid Theory now shut the... [fuck up]".