Hyeonseon Baek (백현선) is a jazz vocalist and songwriter born in Korea and based in New York City. His debut album Longing (2024) puts his tenor voice in front of the pianist Kevin Hays, the bassist Linda Oh, the drummer Jochen Rueckert and the saxophonist Lucas Pino. His releases, his own website and Discogs all spell his name Hyeonseon Baek, the form used here. The Hangul spelling is the Korean reading of the hanja 白炫善, which a Japanese magazine prints beside his name, and a Korean magazine review quoted in his press materials writes it Baek Hyun-sun.

He says he was born in Korea, and no source names a city, a birth date or his citizenship. His biographies place his childhood there. He began singing in a school choir at the age of eight, and in a 2026 interview with the Japanese magazine The Walker's he added that his parents remembered him singing at a neighbourhood karaoke room before he started primary school, and that he also played samulnori, the Korean percussion tradition, as a child. In middle school he listened to rock bands such as Bon Jovi and X Japan and to the fusion groups T-Square and Casiopea, and his first fan devotion was to Mariah Carey. Soul and rhythm and blues came next: his press biography lists Stevie Wonder, Luther Vandross, Donny Hathaway, Ledisi and Aretha Franklin. Recordings by Mel Tormé and Carmen McRae turned him toward jazz, and in the interview he says that hearing Thelonious Monk and John Coltrane stretch their solos made him want to understand how meaning forms in improvisation.

He left Korea about ten years before that 2026 interview, so around 2016, and studied in the Netherlands. Reviewers place him at Maastricht University, and his biography says he completed a bachelor of music in 2019 on a Holland National Excellence Scholarship, the first vocal student to finish the four-year track in three years, with jazz piano as a secondary subject. In his last undergraduate year a university-funded trip to New York left a strong impression, and he moved to the United States for a master of music in jazz voice at the New England Conservatory (class of 2022 in the conservatory's alumni listing), on a merit scholarship. His biography says he studied there with the singer and teacher Dominique Eade and with the pianist Jason Moran, and shared stages with the bassist Dave Holland, the singer Cecile McLorin Salvant and the singer Michael Mayo. In New York he first lived in Greenwich Village.

His biography lists an honorable mention in the Ran Blake Foundation Music Award (2020), an Honor Scholarship from the Seoul National University Alumni Association of New England (2021), and semi-finalist places at the Riga International Jazz Voice competition (2019) and the 7 Virtual Jazz Contest (2024). The Queens Arts Fund named him among its 2025 recipients for a project titled Jazz Bridges: A Cross-Cultural Jazz Concert Experience, and on April 14, 2026 the conservatory's alumni network reported that he had received a 2026 Support for Artists Award from the New York State Council on the Arts. He also teaches voice, improvisation and songwriting privately in the New York area and online.

Longing was recorded on December 19, 2023 at The Bunker Studio in Brooklyn, in a single day and without a rehearsal, as he told The Walker's. Aaron Nevezie recorded and mixed it, Nate Wood mastered it, Baek produced it, and it came out on April 26, 2024 on You&Me Music, preceded by two singles: "West 4th St" on February 16 and the title track on March 21. It has ten tracks. Six are standards: Juan Tizol and Duke Ellington's "Caravan", Joe Henderson's "Black Narcissus", Charles Mingus's "Duke Ellington's Sound of Love" (sung with Mingus's own lyrics), Billy Strayhorn's "Lush Life", Jimmy Rowles's "A Timeless Place" (with lyrics by Norma Winstone) and "Peace". Four are his own: "Longing", "My Temptation", and "West 4th St" in a Korean and an English version, a bop piece inspired by his first neighbourhood in New York, with scat choruses in both. He wrote "Longing" lying on the grass of Washington Square Park watching clouds drift, and "My Temptation" after watching figures appear through the smoke of a pub.

Reception was warm, with reservations. All About Jazz gave it four stars, according to his press materials and Korean Cultural Center listings, and those same sources say Jazz Weekly placed it among its top ten records of 2024, although the title given to that list differs from source to source. Thomas Cunniffe of Jazz History Online heard a timbre close to Chet Baker with far more flexibility, praised his scat and his originals, and noted an occasional odd English pronunciation. Take Effect Reviews gave it 8 out of 10. Filipe Freitas of JazzTrail called it an auspicious debut, Steven James of Jazz in Europe found it an exceptionally strong one, and Peter Gamble of Jazz Journal was more mixed, finding the voice pleasant, the scat variable and the timing a little uncertain at moments, most clearly on the opening "Caravan". His press materials also quote reviews from the Korean magazines Jazz People and MM Jazz and from the Japanese outlets Jazz Life, The Walker's and Music Pen Club.

Since the album he has worked with changing New York groups. The Korean Cultural Center New York listed his June 25, 2024 date at ShapeShifter Lab in Brooklyn with Adam Birnbaum on piano, Sam Dillon on saxophone, Pablo Menares on bass and Jimmy Macbride on drums. The same listings show his quartet Hyeonseon Baek & The Bridge, with Hyuna Park on piano, Koji Cassetta on bass, Chris Ferrari on saxophone and Alex Yoo on drums, at Dada in Queens on December 21, 2025, a quintet with Jacob Chung on tenor saxophone, Allen Farnham on piano, Caleb Tobocman on bass and Tim Horner on drums at Pangea in Manhattan on February 4, 2026, a trio with Farnham at Art Mora Gallery in Ridgefield Park, New Jersey on May 29, 2026, and a quartet with Birnbaum, Tobocman and the drummer Aaron Seeber for what the listing calls his debut at Five Spot Jazz in Manhattan on June 21, 2026. In his 2026 interview he said a second album was already taking shape, with a clearer narrative, more original songs and more of his Korean background in its rhythm, mood and structure.

His own account puts the voice first as an instrument. He says he treats it like a wind instrument, attending to breath, the start and end of each note and the space between notes, and that listening to the band is the most important part of singing. Three vocalists shaped him most, in his words: Carmen McRae for treating a song as a story and rereading each lyric, Kurt Elling for showing that a singer can be one voice among instruments in improvisation, and Mark Murphy for daring. Three albums he names as formative are Stevie Wonder's Songs in the Key of Life, Wayne Shorter's Speak No Evil and an album titled At the Blue Note.

Critics place him in the tradition of the bebop-era singers with a modern songwriter's approach. A reviewer for Bebop Spoken Here, quoted in his press kit, heard a possible successor to Mark Murphy and Jon Hendricks, and a Japanese reviewer also thought of Murphy. The Korean Cultural Center describes the quartet as playing modern, straight-ahead jazz with lyrical storytelling. Jazz Journal found a tenor voice that likes to scat, and Jazz in Europe heard bop phrasing in "West 4th St" and a bossa nova lilt in "My Temptation", where JazzTrail instead heard a bolero feel.