It can be classified as an electropop, dance-pop and EDM-pop song that features an "electro instrumental track" and runs through a down-tempo dance beat.

Spears's voice is heavily synthesized and her pitch constantly shifts; backing vocals are provided by Bloodshy & Avant and Robyn.

The song shares its title with Spears's Las Vegas residency show, Britney: Piece of Me (2013–2017), where it was also performed.

"Piece of Me" was co-written and produced by the Swedish duo Christian Karlsson and Pontus Winnberg, professionally known as Bloodshy & Avant, along with Klas Åhlund.

Winnberg commented that it had always been an unwritten rule not to write songs about Spears's personal life since the label rejected "Sweet Dreams My LA Ex", a response track to Justin Timberlake's "Cry Me a River".

[1] Winnberg stated that Spears was extremely psyched when she came to the studio, where she recorded the song in about half an hour as she had learned the lyrics by heart in her car.

[1] On October 31, 2007, during a radio interview with Ryan Seacrest, Spears talked about the song, saying, "Wherever you go, there's a lot of people who ask questions, and sometimes you don't know their intentions and stuff like that.

[3] "Piece of Me" is an electropop,[4][5] dance-pop[6] and EDM-pop[7] song backed by an "electro instrumental track" and performed in an insistent pop groove.

The track consists of over-the-top vocal distortions, causing a split sound effect, making it difficult to discern which voice is Spears's.

Alex Fletcher of Digital Spy gave "Piece of Me" four stars, calling it "a two fingered-salute to the media hounds and an electro-thudding cry of defiance, warning us that this popstrel is not for turning.

[The opening line] poops from a great height on anything Lily Allen has ever penned and reveals that it's been Spears who's been laughing hardest during her year of zany media antics".

[9] Peter Robinson of The Observer and Margeaux Watson of Entertainment Weekly named "Piece of Me" one of the standout tracks of the album.

"[18] Kelefa Sanneh of The New York Times said "[Bloodshy & Avant] evoke the horror, the exhilaration and (finally) the boredom of [Spears's] overexamined life.

"[20] Stephen Thomas Erlewine of Allmusic commented that "Bloodshy & Avant try desperately to craft a defiant anthem for this tabloid fixture, as she couldn't be bothered to write one on her own".

[21] Chris Wasser from the Irish Independent said the song "drowns slowly under cloggy production and a lyrical theme that for all of its close connection with the trials and tribulations Spears has had to deal with, weren't even penned by the singer who could have very easily recorded her fairly unchallenging input on Blackout in less than a week.

[23] In 2024, Billboard's staff included "Piece of Me" on their "The 100 Greatest Songs About the Music Industry" list, ranking it at number nine.

[27] The song shipped over 1,000,000 copies in the United States, earning a platinum certification by the Recording Industry Association of America (RIAA).

[33] The song has shipped over 70,000 copies in Australia, earning a platinum certification by the Australian Recording Industry Association (ARIA).

[41] "Piece of Me" achieved similar success across continental Europe, peaking inside the top ten in the European Hot 100 Singles chart,[42][43] Austria, Denmark, Finland and Sweden and reaching the top forty in Belgium (Flanders and Wallonia), Czech Republic, Italy and the Netherlands.

[44] The music video for "Piece of Me" was filmed on November 27 and 28, 2007, at the nightclub and restaurant Social Hollywood in Los Angeles, California.

[45] In some scenes of the music video, Spears wore a purple satin dress from American designer Marina Toybina.

[46] Spears reportedly arrived twelve hours late to the set, after spending the day with her sons Sean Preston and Jayden James.

Spears appears in front of a multi-colored, illuminated background wearing a short brown fur vest, a sequined black bra and ripped low-rise jeans.

[48] There are also intercut scenes of Spears wearing a white fur coat tearing down tabloid covers such as In Touch Weekly and creating positive ones, such as "It's Britney, Bitch" and "Exceptional Earner".

During the first chorus, Spears joins the four women, all wearing matching blond bob wigs, dark sunglasses and black trench coats being hounded by paparazzi.

[46] Spears starts flirting with a man and guides him into the women's bathroom, where she discovers he has a hidden camera in his chest.

At the end, the women are seen back at the bedroom watching an entertainment news program, in which the "Britney invasion" from earlier is reported.

The Daily Telegraph commented "Britney – presumably with the help of some serious digital remastering – has turned back the clock, looking every part the young starlet that gave us 'Oops'".

At the end of the performance of "Circus", Spears took off her red jacket that represented a ringmaster, to reveal a black corset encrusted with Swarovski crystals, fishnet stockings and high-heeled laced up boots, designed by Dean and Dan Caten.

[58] Shirley Halperin of The Hollywood Reporter named it one of the best performances of the show along with "3" and "Don't Let Me Be the Last to Know", stating that "ironically enough, [they] were the ones with fewest frills.