It was co-written and produced by Janet and her long-time collaborators Jimmy Jam and Terry Lewis with additional writing by Thomas Lumpkins & additional production by Tommy McClendon and Dem Jointz.
The song debuted on September 3, 2015 on Apple Music's Beats 1 radio station and made available for digital download on the same day Janet officially announced the studio album's release date and tracklist.
It was subsequently released to urban contemporary radio on September 29, 2015 and to Urban adult contemporary radio on October 5, 2015 as the album's second single.
After a period of hiatus and numerous rumours about whether she was recording a new album or not, Janet officially announced her return on May 16, 2015.
She announced she had founded her own label, Rhythm Nation, becoming the first female African-American recording artist to do so while also planning the album to be distributed by BMG as well as preparing herself for a new world tour in the same year.
During the video announcement, an instrumental of the album's first single, "No Sleeep" was previewed and later the full song was released on June 22, 2015.
A week earlier, she also announced that her world tour was called "Unbreakable" and on August 20, 2015, while revealing lyrics of the song "The Great Forever", it was confirmed that "Unbreakable" was also the album's title.
On September 3, 2015, its tracklist was revealed with its title track being one of the seventeen tracks on the album.
During that same day, the song was released to digital download and streaming for those who pre-ordered the album, as well as it premiered on Apple Music's Beats 1 radio station, hosted by Ebro Darden.
On September 29, 2015, the song was officially released to urban contemporary radio stations as the album's second single while being sent to urban adult contemporary radio on October 5, 2015.
"Unbreakable" was written and produced by Janet Jackson, Jimmy Jam and Terry Lewis, with additional writing by Thomas Lumpkins.
It was co-produced by Tommy McClendon with additional production being done by Dem Jointz. Mixing was done by Serban Ghenea and John Hanes served as the song's engineer.
It is a mid-tempo R&B song, with its instrumentation consisting in a thumping bass and a subdued "funky" beat having a "distinctive Janet sound", according to some critics and a soul-sample while Jackson's vocals were considered "breezy" and "soulful".
It starts with a melodic almost a cappella intro with Janet singing, "I lived through my mistakes, it's just a part of growing" before it "segways into a legit bop.
Its pre-chorus is "full of rich harmonies that give a retro—dare we say Jackson 5—vibe," noted Fuse's Mark Sundstrom.
Towards the end, as described by Music Times' Carolyn Menyes, "with a knowing wink, Jackson gives a spoken outro against some finger snaps. 'Hello. It's been a while. Lots to talk about. I'm glad you're still here. I dedicate myself to you. I hope you enjoy,' she says, directly addressing the listeners who have waited so long for a taste of new Jackson music."
Lyrically, "Unbreakable" is a dedication to her fans with Janet expressing thankfulness and praising her loyal fan base and a lover with lines like, "Never for a single moment did I ever go without your love" and "You made me feel wanted, and I want to tell you how important you are to me."
Lewis, one of its producers, commented about its lyrical content, saying, "Some people think of unbreakable as being hard, but I think unbreakable is just being able to be vulnerable and to be able to withstand what comes to you. She’s lived a lot of life in the last few years."
"Unbreakable" peaked at #5 on Billboard's Adult R&B Songs chart.
"Unbreakable" received mostly positive reviews from music critics. Andy Kellman of Allmusic praised the "relaxed and wistful groove" as well as "her lead and background vocals in the chorus arranged to stellar effect," picking the song as one of the album's standout tracks.
While noting that "'Unbreakable' is also the title of a song that began her brother Michael’s final album before he died in 2009," Rob Tannenbaum of Billboard remarked that "the high chorus even sounds like something he might’ve written."
Entertainment Weekly's Kyle Anderson echoed the same thought, claiming she "matches the timbre of his croon" on the track.
Anupa Mistry of Pitchfork called it a "giddy, grateful grown-woman song" while Loren DiBlasi of MTV referred to the song as "classic Janet [with] angelic vocals delivered with timeless R&B style," claiming she "has not lost her touch."
Evan Sawdey of PopMatters called it "a solid mid-tempo groove, something that is all well and good until those multi-layered vocal harmonies come in during the chorus and we’re instantly transplanted back to Janet of old, her familiar coo still sounding remarkably fresh after all this time."
Maura Johnston of Time noted that its "space-age synth [...] blossoms into a sunny-day soul strut," while giving praise towards Jackson’s voice, which according to her, "always notable for the emotion it could pack into even the simplest verse, [being] particularly suited to this type of laid-back R&B."
Writing for Los Angeles Times, Mikael Wood went on to praise Jimmy Jam and Terry Lewis for creating "grand-scaled but meticulously detailed songs that almost sound as though they’ve been under construction since 2008," citing the song as one example, while praising "Jackson’s lush overdubbed harmonies."
Citing "Unbreakable" as one of the album's "affecting surprises", USA Today writer Elysa Gardner named it "brightly infectious" while Carolyn Menyes of Music Times perceived that it "retains the coolness of the first Unbreakable track fans have heard, 'No Sleeep,' while being totally thematically different, focusing on Jackson's return to the world of music."
Mark Sundstrom wrote for Fuse that her was "obsessed" with the track and "sold" on the album, also praising its "rich harmonies" that "totally suits Janet's sexy, sultry vocals."
For Saeed Saeed of The National, the track is "the clearest example of Jackson in her new Zen-pop mode: one can imagine that a few years ago this would have been a more raucous affair. Here, the track is a mid-tempo jam that revolves around a superb vocal sample as Jackson soulfully hails the blessings of reflection."
Michael Arceneaux of Complex opined that the song "successfully conveys the overall theme of the album and Janet’s state of mind—self-assured, truly ready to sing again, and very much in love."
Though noting that the song "loops a sweet-soul sample through the verses like an early Kanye West production," Jon Pareles of The New York Times wrote that "the melodies lack the invincible catchiness of Ms. Jackson’s best songs."