Laufey Lín Bing Jónsdóttir was born in Reykjavík on April 23, 1999, to an Icelandic father and a Chinese mother from Guangzhou who is a classical violinist. Her identical twin sister, Júnía Lín, is also a violinist and later became her creative director. The family spent two years in Washington, D.C., before returning to Reykjavík in 2008. Laufey began piano at four and cello at eight, grew up speaking Mandarin first, and absorbed jazz from her father's record collection, where Ella Fitzgerald and Billie Holiday were prominent. At fifteen she soloed on cello with the Iceland Symphony Orchestra, and in 2014 she reached the final of Ísland Got Talent, Iceland's edition of the show. In 2015 she was a semifinalist on The Voice Iceland, then the youngest contestant in the show's history. She graduated from the Reykjavík College of Music in 2018, where she also studied singing, and went on to Berklee College of Music in Boston on a presidential scholarship, studying cello with Mike Block and graduating in 2021.

Her breakthrough early song was "Street by Street," issued April 6, 2020, which reached number one on Icelandic radio. The EP Typical of Me followed on April 30, 2021, self-released, with most of the songs written in her Berklee dorm room. It includes a jazz-standard reading of "I Wish You Love" that Rolling Stone singled out, and the same year she signed with AWAL, a label that lets artists keep more control of their rights. In 2021 she also hosted a weekly show for BBC Radio 3 called Happy Harmonies, played the London Jazz Festival in November, and released the single "Let You Break My Heart Again" with the Philharmonia Orchestra. A December 2021 single with the singer dodie, "Love to Keep Me Warm," reworked the Ted Shapiro standard "Winter Weather" with a new bridge. She made her American network television debut on Jimmy Kimmel Live! on January 21, 2022.

Everything I Know About Love (AWAL, August 26, 2022) was her first full album: twelve originals written with the producer Spencer Stewart and one standard, Frank Loesser's "I've Never Been in Love Before," with a song titled "Just Like Chet" that nods to Chet Baker, whom she has named, with Ella Fitzgerald, as a leading influence. It reached number three on Billboard's Jazz Albums chart. On October 26 and 27, 2022 she recorded with the Iceland Symphony Orchestra at Harpa Concert Hall in Reykjavík, and the performances were released on March 2, 2023 as the live album A Night at the Symphony, which added Hoagy Carmichael's "The Nearness of You," Cole Porter's "Every Time We Say Goodbye" and an Icelandic song, "Ég veit þú kemur."

Bewitched (AWAL, September 8, 2023) is the record that made her an international name. Written with Stewart and recorded in part with the Philharmonia Orchestra under Robin O'Neill, it has Laufey on vocals, guitar, cello and piano, jazz-side players on several tracks (vibraphonist Simon Moullier, pianist Ted Case, bassist Jonathan Richards, drummers Ryan Shaw and Jordan Rose), and a cover of Erroll Garner and Johnny Burke's "Misty." It debuted at number 23 on the Billboard 200 and at number one on the Jazz Albums chart, and it was certified gold in the United States on March 11, 2025. She played the Montreux Jazz Festival on July 11, 2023. At the 66th Grammy Awards on February 4, 2024 she won Best Traditional Pop Vocal Album, and the same night she played cello alongside Billy Joel on his live debut of "Turn the Lights Back On." The deluxe Bewitched: The Goddess Edition followed on April 26, 2024, adding Jimmy Van Heusen and Burke's "It Could Happen to You." The Bewitched Tour included London's Royal Albert Hall on May 16, 2024 and a sold-out Hollywood Bowl show on August 7, 2024 with the Los Angeles Philharmonic under Thomas Wilkins, directed by Sam Wrench and released as the concert film A Night at the Symphony: Hollywood Bowl on December 6, 2024.

A Matter of Time (Vingolf Recordings and AWAL, August 22, 2025) was produced with Stewart and, on two songs, Aaron Dessner of The National, with the Iceland Symphony Orchestra on "Forget-Me-Not." Laufey sings every track and plays cello on most of them. It debuted at number four on the Billboard 200 and number one on the Top Jazz Albums chart, and at number three in the United Kingdom, her first top-ten album there. It won her a second Best Traditional Pop Vocal Album Grammy at the 68th Grammy Awards on February 1, 2026; one of the losing nominees was Barbra Streisand's The Secret of Life: Partners, Volume Two, which carries Streisand's duet with Laufey on "Letter to My 13 Year Old Self." On January 1, 2026 the President of Iceland made her a Knight of the Order of the Falcon. The extended edition A Matter of Time: The Final Hour came out on April 10, 2026, and the live double LP A Matter of Time: Live at Madison Square Garden was a Record Store Day release on April 18, 2026. Her 70-date A Matter of Time tour ended in Mexico City in September 2026, and on September 16, 2026 she signed with Interscope Records and Verve Records, her first major-label deal. She is working on new music.

Laufey sings in a low, rounded voice, often described as a contralto, over arrangements that borrow from jazz ballads, bossa nova, mid-century orchestral pop and the classical repertoire she trained on, and she writes most of the songs she records. She has said that when she began singing at twelve, her lower voice connected more with Ella Fitzgerald and Nat King Cole than with current pop, and she has named Fitzgerald as her favorite musician and Chet Baker as another leading influence. Her other stated influences include Billie Holiday, Norah Jones, Taylor Swift, Billie Eilish and Adele, and she has said she hopes to do for jazz what Swift has done for pop and country. She calls her own music jazz or jazz pop and, in one interview, contemporary jazz meeting classical.

Whether the music is jazz is a standing argument that critics have not settled. Her records chart high on jazz lists, include standards by Garner, Burke, Loesser, Carmichael, Porter and Van Heusen, and she has played jazz festival stages (the London Jazz Festival in 2021, Montreux in 2023), but both of her Grammy wins are in the traditional pop category rather than a jazz one. In a January 2024 NPR essay, the critic Ann Powers argued that she belongs in traditional pop, hearing in her ballad delivery the lineage of Peggy Lee and Julie London, and faulting her for showing little awareness of the current international jazz scene. AllMusic reported in 2024 that she has said, in a podcast interview, that she had never been to a jazz club and found them intimidating, and that she told Billboard she was lucky to have been born into jazz and wants to lower the barriers for newcomers. A Matter of Time leans further toward pop and a more personal register than its predecessors, and she has called it her most confident and most ambitious album. In March 2026 she also recorded the modal ballad "Blue in Green" from Miles Davis's Kind of Blue for an Amazon Music Original. The jazz tags in the header reflect the standards and jazz-chart side of her work; the pop side is just as real.