Gaining attention from self-released music on social media platforms, she signed with Astralwerks in 2014 and released a debut extended play (EP), Room 93, in October of that year.

It was certifiied double platinum by the Recording Industry Association of America (RIAA), along with its singles "Colors", "Gasoline" and "New Americana", the latter of which became her first entry on the US Billboard Hot 100 at number 60.

In 2016, Halsey co-performed with the Chainsmokers on their single "Closer", which topped the charts in the US and ten countries, while receiving 14× platinum certification by the RIAA.

[24] After graduating, Frangipane enrolled in the Rhode Island School of Design, but she withdrew due to financial hardship and instead attended community college.

[10] Frangipane started writing music when she was 17, and in 2012, she began posting videos to social media sites such as YouTube and Kik, and in particular Tumblr, under the username se7enteenblack.

[26] It received positive reviews from music critics,[43][44] with Joe Levy of Rolling Stone citing Halsey as a "new Tumblr popstar with a knack for sticky imagery".

[52] The latter three singles achieved minor commercial success: "New Americana" reached number 60 on the US Billboard Hot 100,[53] "Castle" was rerecorded for the soundtrack of the 2016 film The Huntsman: Winter's War.

[55][56] The song was not officially released as a single, though it entered the top forty of the Billboard Hot 100 and was certified Gold in the US and Silver in the United Kingdom.

[57] In February 2016, Halsey was one of four female performers to partner with MAC cosmetics for their Future Forward line; she released a lipstick named after herself.

[77] It consisted of more "radio friendly" songs in comparison to her previous work, which she attributed to her desire to prove she was "more than capable" of creating "radio-ready" music.

[78] Much like her debut, Hopeless Fountain Kingdom is a concept album that revolves around a pair of lovers in a tale based on Romeo and Juliet; the project was inspired by her breakup with Lido.

[84] To promote the record, Halsey embarked on the Hopeless Fountain Kingdom World Tour, which began on September 29, 2017, her twenty-third birthday.

[88][89][90] In December, Halsey's collaboration with then-boyfriend G-Eazy, "Him & I", was released, and later peaked at number 14 on the Billboard Hot 100[91] and achieved a 2× Platinum certification by the RIAA in the US.

[94] On January 13, 2018, Halsey was featured as a musical guest on the American television variety show Saturday Night Live, where she performed "Bad at Love" and "Him & I", with G-Eazy.

[121] On April 19, she and 29 other musical acts were featured on the Lil Dicky song "Earth", a charity single about climate change awareness.

[138] On August 27, 2021, Halsey released her fourth studio album, If I Can't Have Love, I Want Power, with little prior promotion.

"[150] Capitol Records eventually conceded on May 31, 2022, amid criticism and scrutiny from a variety of music artists, and set a release date for the song of June 9, 2022.

[161] She performed the songs "Ya'aburnee" and "Bells in Santa Fe", from If I Can't Have Love, I Want Power live for the first time.

[162] On June 4, 2024, Halsey released "The End", the lead promotional single of her fifth studio album The Great Impersonator, which deals with her health battles.

[166] On September 6, she released a fourth single, "Ego", alongside a video clip, which she wrote and directed, playing a double role in it where the characters try to kill each other.

[167][168] She also performed it at the 2024 MTV Video Music Awards, embracing more its 1990s aesthetic by creating her ideal "90s garage rock band" alongside Victoria De Angelis on bass, Jazzelle Zanaughtti on synths and Maya Stepansky on drums.

[170] In order to reveal the album's different covers, she organized a hunt of clues an campsules with items reminding of different decades around major cities in the world for her fans to find.

[177][178] She has also mentioned a Long Island rock band, Brand New, as both an influence and a favorite of hers, once changing her biography on Instagram to "The Devil and God Are Raging Inside Me", a reference to their third album.

[180] Her other influences include Mick Jagger, David Bowie, Bob Dylan, Jimi Hendrix,[181] Christina Aguilera,[182] Marilyn Manson, Beck,[183] Kanye West,[184] Amy Winehouse,[185] the Weeknd,[186] Alex Turner,[187][188] Bright Eyes,[189] and the Wonder Years.

[209] The New York Times' Jon Caramanica noted, "Halsey arrived as part of a slew of female pop rebels who emerged in the wake of Lorde's early-2010s recalibration of the genre's operating hierarchies.

"[210] When speaking of Badlands, Billboard stated, "Halsey's larger-than-life vision combines the synthy darkness of Lorde, the neon-pop chutzpah of Miley Cyrus and the flickering film noir of Lana Del Rey.

[244] She completed her speech by requesting all—"Black, Asian, poor, wealthy, trans, cis, Muslim, Christian"—sexual assault victims to listen and support each other.

[122] In May 2020, Halsey, alongside Yungblud, joined protests in Los Angeles for racial justice in the wake of the murder of George Floyd.

[269] The two co-parent, with Halsey also requesting that Aydin have reasonable visitation rights and the ability to make health and education decisions for their son.

[273] On December 11, 2021, Halsey informed fans via Twitter that she was diagnosed with ADHD in high school, and that she assumed she just grew out of it; however, she is now medicated for it as a result of seeking mental health treatment during the COVID-19 pandemic.