Big Machine Records released the song on August 24, 2017, after approximately one year of Swift's hiatus due to the controversies that affected her "America's Sweetheart" public image throughout 2016.

"Look What You Made Me Do" has an electronic production combining electropop, dance-pop, progressive pop, and synth-punk with elements of hip hop, electroclash, industrial, and electro.

In the United States, the single peaked atop the Billboard Hot 100 with the highest sales week of 2017 and was certified four-times platinum by the Recording Industry Association of America.

[3] Swift's popularity turned her into a media fixation,[4] and her once-wholesome "America's Sweetheart" reputation was tarnished by short-lived romantic relationships and public celebrity controversies, including a feud with rapper Kanye West and his then-wife, media personality Kim Kardashian, over West's song "Famous" (2016), in which he claims he made Swift a success ("I made that bitch famous").

[7][9] Detractors regarded Swift as fake and calculating, a conclusion that surmounted after years of what they saw as a deliberate maneuver to carefully cultivate her public image.

[10][11] Swift became increasingly reticent on social media despite a large following and avoided the press amidst the commotion and ultimately withdrew from public appearances.

[16] In the following days, she uploaded silent, black-and-white short videos of CGI snakes onto social media, which attracted widespread press attention.

[20] The following day, she unveiled the lead single from the album, "Look What You Made Me Do",[21][22] which was released for streaming and download on digital platforms by Big Machine Records.

[24] The lyric video features prominent snake imagery, depicting the chorus with an ouroboros,[25] and its graphics were influenced by the aesthetics of Saul Bass for the 1958 film Vertigo.

[30][31][32][33] Swift wrote and produced "Look What You Made Me Do" with Jack Antonoff, who also programmed the track and played its instruments, recorded at Rough Customer Studio in Brooklyn.

[42] Jon Pareles commented that the piano and strings in the pre-chorus and bridge gave them a "melodramatic, emotional" feel, whereas Swift's repeating the title in the chorus sounded "vindictive, mocking, dismissive, even a little playful".

[26][43][44][45] NPR's Lars Gotrich said that the beats and vocals evoked electroclash,[45] Rolling Stone's Brittany Spanos said it was a dance-pop song,[46] and Fact's Chal Ravens deemed it progressive pop.

[50] In the bridge, Swift's character threatens to give her enemies nightmares ("I don't trust nobody and nobody trusts me/ I’ll be the actress, starring in your bad dreams") and tells that the old version of her was dead, delivered through a sound effect that resembles a telephone call: "The old Taylor can't come to the phone right now/ Why?/ 'Cause she's dead";[46][53] Swift said that these lyrics were the most important part of the song.

[33][58][59] Some considered the single a fierce return and an interesting move for Swift to reclaim her public narrative, whereas others found the production and themes vindictive, harsh, and off-putting.

[61] The Telegraph's Sarah Carson praised the song, deeming Swift and Antonoff's work as "blowing past the production clichés of clap tracks and hiccuped syllabic hooks that have proliferated across Top 40 fare in recent years with boldly inventive textures and fresh melodic, rhythmic and sonic accents".

[38] Variety's Chris Willman also praised Swift's embrace of darker-styled pop music and the stylistic conflict between the song's pre-chorus and chorus.

[52] Mark Harris, writing for Vulture, thought of Swift's song as a pop art anthem for the Trump era in how she reappropriates her public feuds as empowering badges of honor without acknowledging her responsibility or blame.

[26] Lindsay Zoladz of The Ringer said, "Unleashed on a deeply confused public late Thursday night, the song is a strange collage of retro reference points: mid-aughts Gossip Girl placement pop, the soundtrack to Disney's live-action Maleficent, and — yes, really — Right Said Fred's "I'm Too Sexy", except devoid of the self-effacing humor and wit.

The next scene shows Swift in a bathtub filled with diamonds, with a necklace spelling out "No" next to a ring, supposedly sending up tabloid press rumors of her past romantic relationships.

Swift later crashes her golden Bugatti Veyron on a post and sings the song's chorus holding a Grammy as the paparazzi take photos.

In the opening scene, there is a subtle "Nils Sjöberg" tombstone shown when Swift is digging up a grave, referencing the pseudonym she used for a songwriting credit on Calvin Harris' 2016 single "This Is What You Came For".

However, given the video's theme of mocking the media, the car crash scene likely makes fun of the theory that Swift's real fallout with Perry was a dramatized act for publicity and album material.

[110] Swift leading an army of tall, skinny, and robotic women at a "Squad U" gathering poked fun at the media's accusations that her close group of friends were artificial and had unrealistic body shapes.

During the bridge, Swift stands on a mountain of clones of her past selves, which reiterates that she is leaving behind her "America's Sweetheart" image and embracing her newfound role as an evil "snake".

[110] The video's ending features an assembly of "old Taylors" in front of a private jet who are talking amongst one another and making snide references to the many false and exaggerated media portrayals of her throughout her career.

[118][119][120] The song was also a regular part of her set list for the Reputation Stadium Tour, with a tilted throne and golden snakes; while there are snakes on the high screen in the back during the part where she sings, "I don't trust nobody and nobody trust me, I'll be the actress starring in your bad dreams", a large floating cobra appears onstage with the line from the bridge announcing the death of the "Old Taylor" spoken by comedian Tiffany Haddish.

[123] On the Eras Tour, while Swift is performing "Look What You Made Me Do," she is surrounded by her backup singers and dancers, who are dressed as various past versions of herself and trapped inside large clear boxes.

[127] In the South Park episode "Moss Piglets", the water bears in Timmy and Jimmy's experiment for the science fair dance to the song in response to Swift's singing.

[129] A cover version of "Look What You Made Me Do" was recorded by the band Jack Leopards & the Dolphin Club, and produced by Antonoff and Nils Sjöberg, the latter being a pseudonym that Swift first used as a co-writer for the song "This Is What You Came For" by Calvin Harris featuring Rihanna.

The cover was featured in the opening credits of "Beautiful Monster", an episode of the television show Killing Eve that aired on May 24, 2020, and subsequently released on digital music platforms.