Having been surrounded by what she described as unconditional love, she co-wrote it with the song's producers Dr. Luke, Max Martin and Cirkut to reflect that feeling.

The single release was promoted with an Instagram-based campaign, a lyric video directed by Aya Tanimura and live performances—one of the latter, at the American Music Awards of 2013, was the center of controversy due to accusations of cultural appropriation.

Brent Bonacorso served as the director for the track's music video, which adopts the theme of love and uses a series of metaphors to enrich its concept.

She also mentioned that she wrote the song bearing in mind the sentiments she had felt during her UNICEF humanitarian trip to Madagascar in April 2013.

It paces at a moderately fast metronome, at approximately 126-132 beats per minute, while it is set at a 4/4 time signature, following a chord progression of Em–C–G–D.

Lyrically, Jason Lipshutz from Billboard deemed it the "most mature offering" on Prism, claiming it served as a "predicate" to Perry's 2010 single "Teenage Dream".

[18] Fans were invited to participate in an Instagram-based campaign, in which they could upload a photo of "what unconditional love meant to them", along with their story and location in order for it to appear on a "Prism map of the world".

[22] John Walker from MTV praised the track and felt that the song could be written from the perspective of Jesus and denoted possible Christian undertones lying.

[23] Kitty Empire of The Guardian reckoned the track was "ungainly" and "adverbial";[24] Helen Brown of The Daily Telegraph wrote that its lyrics had "self-help lingo", although she remarked that "Perry's genuine faith in it, along with her wit and sense of fun, powers her through".

[25] Kevin Fallon from The Daily Beast regarded it as adequate for a Nicholas Sparks-adapted movie, however, he noted that Perry's vocal delivery saved the song of being "schmaltzy".

[27] Glenn Gamboa of Newsday thought Perry "ruined" the track, which she deemed "decent", for pronouncing the song title as "uncondiSHUNally".

[28] In his review for Prism, Jon Dolan from Rolling Stone wrote that the song "set stark revelations to torrential Euro splendor".

[30] Trent Wolfe of The Verge, however, thought the song was part of the group of the Prism tracks that could "benefit from a preciously strummed six-string" instead of "beats and synths".

[31] Digital Spy's Robert Copsey awarded the song with a four out of five points rating, writing that Perry sounded "effortless" as compared to her peers.

It then gradually descended down the charts and has spent a total of 13 weeks, marking it as Perry's lowest spanning single in Australia.

The song however received a platinum certification by the Australian Recording Industry Association (ARIA), denoting more than 70,000 copies sold.

As the song essentially discusses the feeling of love, the video itself sees Perry amidst scenarios which indirectly refer to the power of it.

[62] The video is set in two different spaces, as Perry is found both in a snowy background and in a ballroom surrounded by dancers, which are mostly dressed in black apparel.

By the second repetition of the chorus, a bed gets lit on fire, which the director included to refer to love that "can burn you like an inferno".

As the song reaches its climax, Perry gets hit by a car, with tiny broken debris from it shattering behind her, while she remains stationary and unharmed.

This scene cuts back to the ballroom, where Perry is surrounded by a similar explosion of "colorful" flowers, which is used to contrast the more violent nature of falling in love and the softer part of it, the "joyful and wonderful" feelings.

[74] Perry performed a stripped-down version of the song on the December 20, 2013 episodes of The Ellen DeGeneres Show and Alan Carr: Chatty Man.