Youngjoo Song (송영주) is a pianist and composer who grew up in Seoul and has divided her working life between Seoul and New York. Discogs, Apple Music and much of the Korean press write her name as Song Young-joo or Song Young Joo, family name first, while her album covers since 2011 print Youngjoo Song. She has won the Korean Music Awards four times, for Love Never Fails (2010), Tale of a City (2012), the solo piano album Late Fall (2019) and Atmosphere, which took Best Jazz Album at the 20th ceremony in 2023. MusicBrainz gives her birth date as August 8, 1972, and Melon lists 1973; interviews that state her age fit 1972. She teaches in the practical music department of Seoul Theological University.

She was raised in a pastor's family and grew up playing and hearing music in church. She studied classical piano at Sookmyung Women's University while already working as a studio and live pianist in Korean contemporary Christian music. In a 2005 Hankook Ilbo interview she said that she first heard the pianist Brad Mehldau in 1999, just after finishing university, and that it changed her direction; in a 2018 interview she added that she had gone abroad to study harmony without knowing who Miles Davis was. She went to the Berklee College of Music for jazz performance on piano and then took a master's degree in jazz performance at the Manhattan School of Music, where her Melon biography says she was the lead pianist of the Concert Big Band and names George Garzone, Bob Mintzer, Nancy Marano, Ed Tomassi and Steve Slagle among the musicians she worked with. By the Hankook Ilbo's account she stayed in New York on an artist visa, playing clubs, teaching lessons and arranging, and she returned to Korea in June 2004.

Her debut, Turning Point, came out in Korea in 2005. The Hankook Ilbo wrote that it startled the Korean jazz scene because some pieces fitted the five and seven beat cycles of samulnori percussion into jazz, an idea she said came from living abroad, and that it had been planned as the first of three albums under a contract with a Nashville label, to be issued in the United States and Korea together. The American release was a hymn album, A Flavor for Every Taste: Jazz Meets Hymns (Cool Springs Records, recorded in Brentwood, Tennessee), which Discogs lists under the name JuJu Song, with the Korean edition following in 2006 as Jazz Meets Hymns. Journey (September 21, 2006, Stomp Music and EMI Music Korea) and Free to Fly (2007) followed; Free to Fly was a nominee for the 2009 Korean Music Awards. In those years she also taught at Seoul National University and Soongsil University, according to the 2005 article, and she was named best pianist in the readers' poll of the magazine Jazz People in 2008 and 2010.

Love Never Fails (Stomp Music, May 14, 2009) won the jazz album category at the 7th Korean Music Awards in 2010. In September 2010 she completed an Artist Diploma in jazz performance at SUNY Purchase and stayed in New York for about three and a half to four years. She told the jazz writer Hwang Deok-ho in 2018 that she had gone partly to recharge and partly to work with New York musicians, and that being unknown there after years of recognition in Seoul was harder than her student days. Tale of a City (Sony Music Korea, September 15, 2011) came out of those years and carries the names of Steve Wilson, Kendrick Scott, Vicente Archer, Rogerio Boccato and Gretchen Parlato on its cover; it won the performance category at the 9th Korean Music Awards in 2012. Her quartet, with Mark Turner on tenor saxophone in a 2012 listing, played the EBS Space series in Seoul that June. She appeared at Blue Note New York as a headliner (by the Hankook Ilbo's count five times by June 2015; her promotional biography calls her the first woman from South Korea to headline there), at the Blue Note Jazz Festival in 2013, 2014 and 2015, and in Malaysia, Singapore and China on a tour in April 2013. In January 2014 she brought the Japanese bassist Kengo Nakamura and the American drummer Gene Jackson to Seoul, Ulsan and Busan for trio dates.

Between (Sony Music Korea, 2014) is ten of her own compositions; it was a nominee at the 2015 Korean Music Awards. For the tenth anniversary of her debut she released Reflection in October 2015, nine pieces from her earlier albums re-recorded with a front line of alto, soprano and tenor saxophones, clarinet, flute, trumpet, flugelhorn and trombone over piano, bass and drums, played by six New York musicians; it was nominated at the 2016 awards. She told the Hankook Ilbo that adding winds to a piano trio felt like turning a short story into a novel. Back in Seoul, she accepted an invitation to play a solo recital in August 2017, found it frightening, and decided to try again: on December 22, 2017 she recorded a solo concert at the JCC Art Center in Hyehwa-dong. Late Fall (Blue Room Music Korea, April 26, 2018) is nine tracks from that evening, eight of them earlier compositions and one new piece, "Reminiscence". TenAsia described it as the first live solo piano album by a Korean jazz musician. She issued it without editing beyond removing applause, and it won the instrumental category at the 16th Korean Music Awards in 2019.

Collaboration has been steady since. Sogno (2018) pairs the tenor Hyunsoo Kim with the guitarist Ham Chun-ho and her; Tribute (April 30, 2019) is a piano and voice album of songs by women with the vocalist Sunny Kim, whose version of Joni Mitchell's "A Case of You" a CBS Nocut News critic praised in 2020; and the third volume of her hymn series, Jazz Meets Hymns 3, appeared on November 23, 2021. Atmosphere (Blue Room Music Korea, October 18, 2022), recorded at Sear Sound in New York on June 29 and 30, 2022 with Marcus Gilmore on drums, Vicente Archer on bass and John Ellis on tenor saxophone according to Namuwiki's listing, won Best Jazz Album at the 20th Korean Music Awards and was also a nominee for Album of the Year, which went to 250's Ppong. Her quartet recorded an EP for the Seoul Forest Jazz Festival with Kim Suyoung and the band Golden Donut in October 2024.

On October 19, 2026 she released Simplicity, a solo piano album marking twenty years since her debut. Sports Kyunghyang reports that every track was recorded in one take and calls it her eleventh studio album, though counts of her albums differ from source to source. A concert is announced for December 12 at the JCC Art Center, with solo pieces from the new record and her best known songs of two decades reworked for trio.

Outside jazz she is a sought-after session pianist and arranger in Korean pop. Her credits on Discogs include records by Super Junior, SHINee, TVXQ, B.A.P, Taemin, Chen, Kyuhyun and Red Velvet, and she told the Hankook Ilbo and Channel Yes24 that she has played for Kim Dong-ryul, Rain, BoA and others and sees those jobs as a chance to introduce jazz to pop audiences. In February 2017 SM Station released "Curtain", a single credited to Suho of EXO and her. She has also been a featured pianist on tracks by other Korean artists, among them the harmonica player Jeon Jeduk.

She names Keith Jarrett, Brad Mehldau and Bill Evans as the pianists who shaped her, and in 2018 added Fred Hersch to the solo pianists she admired. Her own writing leans toward lyrical melodies and a reflective, sometimes melancholy tone that she says comes from everyday experience and travel rather than from analysing standards; "Late Fall" was her response to a scene in a film in which an actress searches for her partner. She distrusts displays of technique, telling the Hankook Ilbo and Channel Yes24 that feeling and technique must be balanced and that her playing should show who she is.

Gospel is the other root. She has said that the hymns she heard and played in church as a child sit underneath whatever she plays, whether jazz or classical, and her hymn albums mix standards of the Protestant repertoire with jazz harmony. In 2018 she said that she would like to record a duo of gospel songs with a bassist in the manner of Hank Jones and Charlie Haden. Her debut put Korean rhythmic cycles into jazz. Her quartets and quintets with New York players lean toward modern mainstream and post-bop playing, while the solo albums Late Fall and Simplicity are improvised and spare.