Music critics described the production as cheery or campy; they either found the track catchy and tongue-in-cheek or deemed it immature and cloying.

It reached the top ten in many territories and received platinum or higher certifications in Australia, Brazil, Canada, New Zealand, Poland, and the United Kingdom.

[1] On April 25, various news outlets reported that a mural of a butterfly in The Gulch neighborhood of Nashville, Tennessee, painted by street artist Kelsey Montague,[2] was connected with the upcoming release.

[16] Roisin O'Connor of The Independent wrote that "Swift once again proves her mastery of the infectious pop hook in one of the most drastic reinventions of her career to date".

Is Everything Wrong With Pop", The Atlantic's Spencer Kornhaber wrote that the song "has almost none of the elements that once made [Swift] interesting, but it does have a dolphin screech for a chorus".

"are just surface messaging about self-love and acceptance, the kind of hollow #positivity that is slapped on greeting cards and slogan t-shirts and sold as empowering".

[22] Slate's Carl Wilson called it "fluffy and immaterial", adding that Swift and Urie "just traipse through a kiss-and-make-up number out of a teen musical".

[23] Writing for The Daily Telegraph, Kate Solomon opined that "she's concocted what might be her most pop song to date," and went on to say that "the low point might be Swift shouting out, 'Spelling is fun, kids!'

[24] The Spinoff's Alice Webb-Liddall wrote "I was prepared to like it until Taylor yelled 'Spelling is fun' and from that point in the video I felt a little bit sick".

[25] Writing for The Independent, Alexandra Pollard stated that the song is "so blandly uncontroversial that there is literally nothing to say about it", and that it "has proven something of a damp squib".

debuted at number 100 on the Billboard Hot 100, and ascended 98 spots to its peak of number two in its second week, behind "Old Town Road" by Lil Nas X featuring Billy Ray Cyrus, becoming the biggest single-week jump in the Hot 100's history, beating the record previously set by Kelly Clarkson's "My Life Would Suck Without You".

debuted and peaked at number three on the UK Singles Chart, becoming Swift's 12th top ten hit song in Britain.

It also sold 67,000 downloads within its first week, making it Britain's second biggest female sales debut of 2019, behind Ariana Grande's "7 Rings".

debuted and peaked at number two on the ARIA Singles Chart dated May 4, 2019, becoming Swift's seventeenth top ten hit in Australia.

On April 27, 2019, it was announced that the music video amassed 65.2 million views within its first day of release, breaking the 24-hour Vevo record previously held by Ariana Grande's "Thank U, Next".

It was revealed that "You Need to Calm Down", a line Urie says to Swift at the beginning in French, would be the second single, and an "old-timey, 1940s-sounding instrumental version" of the song plays in the background in the same scene.

[59] The video pans up to an apartment unit in which Swift and Urie are engaging in an argument in French, with hard subtitles provided.

Urie looks out onto the street from the apartment and jumps down the balcony on an umbrella Mary Poppins-style wearing a floral print suit.

He lands on the roof of a building with a unicorn-shaped eave, where Swift is seen sitting at the edge in a pink dress that turns into a waterfall.

Swift has revealed on an Instagram livestream that this is a reference to her 2014 song "Welcome to New York", where she sings "kaleidoscope of loud heartbeats under coats".

[61] Urie and Swift then sing on a heart-shaped pinkish-orange stage, joined with a band of angels and go-go dancers wearing 1960s mod style clothing.

As the bridge plays, Swift and Urie don blue marching band uniforms and dance with a group of dancers in the same attire, but pink.

The video ends with the duo entering the same apartment building with an umbrella as the bubblegum rain continues on the street in the night.

In her Netflix documentary Miss Americana, Swift describes the concept of the music video as having been based on the song's message of individualism and self-empowerment, by demonstrating the hobbies and characteristics that make herself and Urie unique: emo kids and musical theatre for Urie, and cats, gay pride, and cowboy boots for Swift.

[64] Chris Willman of Variety described the music video as a "phantasmagorical delight" that induces an instant "sugar rush" in a "bubblegum psychedelia".

[75] She performed the song along with "You Need to Calm Down" and "Shake It Off" at a Good Morning America concert in Central Park on August 22.

[76] On September 9, Swift performed the song at the City of Lover one-off concert at L'Olympia in Paris, France.

by Taiwanese singer Tzuyu, a member of South Korean girl group Twice, featuring Bang Chan of Stray Kids, was released.