Music critics believed "Obsessed" achieved an edgier sound than Rodrigo's previous output and directed praise towards its upbeat nature and lyrics.

Mitch Ryan directed the music video for "Obsessed", which depicts Rodrigo facing her partner's ex-girlfriends in a beauty pageant and performing the song in an adjoining room.

These performances received positive reviews alongside comparisons to 1990s rock artists, and the song attained viral popularity on video-sharing service TikTok.

Olivia Rodrigo conceived her second studio album, Guts (2023), at the age of 19, while experiencing "lots of confusion, mistakes, awkwardness & good old fashioned teen angst".

[6][7][8] Two days before the album's release, Rodrigo uploaded a parody infomercial which teased the names of four additional tracks, including "Obsessed".

[13][14][15] In 2024, "Obsessed" became the only hidden track to be included on the set list of Rodrigo's Guts World Tour (2024–2025), and it attained viral popularity on video-sharing service TikTok.

[16][17] In March 2024, Rodrigo's fan hotline began playing a snippet of "Obsessed",[18] and it was subsequently announced as a single alongside the album's deluxe edition, Guts (Spilled) (2024).

[25][28] Eddino Abdul Hadi of The Straits Times likened this dynamic to old alternative rock bands, and Aadya Dusad of the South China Morning Post compared the song to the work of Avril Lavigne.

[29] Rodrigo admits to spending unusual amounts of time thinking about and looking at pictures of the partner's ex and researching personal details like her astrological sign and blood type.

[36][37] Notion found the song catchy, and Uproxx's Lexi Lane described it as a standout and included it in the website's weekly roundup of the Best New Pop Music.

Including it at number 25 in Billboard's list of the best songs of 2024 as of June, Andrew Unterberger stated that it was her "most deliciously thrashing" and "least-likely radio hit", unsure if its production hurt or helped its commercial prospects.

[35][62] The hairstylist Clayton Hawkins styled Rodrigo's hair into rough pixie cut bangs, with gentle flowing Bohemian waves reminiscent of the 1970s and two long braids.

Her outfit was a gothic and bare-shouldered black prom dress with an overlay and Steve Madden's Lotti Mary Jane loafers and socks.

[28] Rolling Stone's Tomás Mier described the video as a "fever dream", and Rania Aniftos of Billboard believed the concept flawlessly complements its lyrics about envy.

[66][67] On the Guts World Tour, "Obsessed" appears as part of a set of rock-oriented songs, alongside "Brutal" (2021), "All-American Bitch" (2023), "Good 4 U" (2021), and "Get Him Back!"

[68] After a white sheet burning to ashes is projected on a screen during a progressive rock-metal interlude, symbolizing "the death of innocence" according to The Tennessean's Audrey Gibbs, Rodrigo sings "Brutal".

[72] Kevin C. Johnson of St. Louis Post-Dispatch considered it the show's "most badass moment", and Melissa Ruggieri of USA Today praised the use of camera effects.

Michael Rietmulder of The Seattle Times thought it was influenced by grunge, and Sarah John of Nylon believed it was one of the moments that encapsulated the "pop-punk and riot-grrrl sensibilities" demonstrated throughout the show.