Kim Ju Hwan (김주환) is a South Korean jazz vocalist based in Jeonju who has spent his career on the American songbook. Korean newspapers describe him as one of the few male jazz singers in the country, and a Seoul Economic Daily headline of 2016 called him "Korea's Tony Bennett". He debuted with the single Sophisticated in November 2011 and has since released eleven regular albums, from My Favorite Things (2012) to After Midnight: Still in the Moonlight (2024), a voice and piano duo with the Japanese pianist Yuki Futami. Three of those records were nominees for the Korean Music Awards' jazz vocal prize: My Funny Valentine at the 19th awards in 2022, Candy at the 20th in 2023 and After Midnight at the 22nd in 2025. His birth date and birthplace are not published; ages given in the press (29 in 2013, 31 in 2016, 36 in 2021) put his birth around 1985.

Seoul Economic Daily's 2016 interview, which gave his age as 31, says he listened to black soul music when he was young and applied to an agency to become a pop singer, then turned to jazz in his early twenties after hearing Jamie Cullum, Michael Bublé and Sting. EBS, in its 2015 announcement of a concert for him, tells the same story of a would-be pop singer who came across jazz by chance. His first release was the single Sophisticated in November 2011, two standards: "All The Things You Are", which the release note says he sang in the manner of Rosemary Clooney's version, and "Everything Happens To Me" as a bossa nova. The first full album, My Favorite Things, followed in October 2012 on Noah ENT with nine tracks, among them "Come Rain Or Come Shine", "Misty" and "Black Coffee", arranged in a broad pop-jazz manner.

After that he recorded almost every year, and funded the records himself according to the 2016 interview. The Best Gift (April 2013) came with a liner essay by the critic Choi Kyu-yong, who wrote that when the producer Hong Ji-hyun sent him the finished recording he took the singer for a foreign vocalist, and called him the only Korean vocalist who kept the traditional image of a jazz singer. Warm Like Love (February 2014), on Mirrorball Music, includes a duet on "Baby It's Cold Outside" with the vocalist Jang Jeong-mi, and Tranquility (November 2014) adds instrumental versions of five of its tracks. EBS Space Gonggam announced a two-night programme for March 9 and 10, 2015, shared with the saxophonist Choi Kyung-sik, and described him as having released four regular albums in three years. A Christmas album, A Very Happy Christmas With You, came out in November 2015.

His 2016 album The Music Of Cole Porter & Harold Arlen: The Gal That Got Away (October 20, 2016) was the first of the songbook records he now favors: thirteen vocal tracks, arranged by Kim and the pianist Kim Ji-hoon, with the trumpeters Bae Seon-yong and Ju-han Lee and the guest vocalist Yeny Kang on "I've Got The World On A String". In the Seoul Economic Daily interview of November 2016 he said he arranges classic standards rather than write songs of his own, so as not to damage the tradition, that he had been nominated in the jazz and crossover category of the Korean Popular Music Awards (now the Korean Music Awards) and in the vocal category of the Korea Jazz Festival's leaders poll, and that he planned to record an album of pop and Korean material. Close To You (December 2017), his seventh regular album, was announced as a Richard Rodgers and George Gershwin songbook that grew to twelve songs, among them "City of Stars" from La La Land, arranged for acoustic guitar, trumpet and bass, and "Waltz for Debby". Sports Kyunghyang reported a release concert at Formtech Works Hall near Hapjeong Station on January 27, 2018. Skyfall (May 29, 2020), his eighth, was recorded at Yagi Studio in Seoul in October 2019 and turned to film themes: "Skyfall", "Beauty and the Beast", "Lost Stars" from Begin Again, "Falling Slowly" from Once and "Shape of My Heart" from Leon, with Jeon Yong-jun on piano, Kim Dae-ho on bass and arrangements, Ha Beom-seok on guitar, Kim Yeong-jin on drums, Hong Tae-hun on trumpet and the singer Yoo Myeong-ji as guest. The vocalist Woong San is quoted in the release notes recommending it.

My Funny Valentine: Kim Ju Hwan Sings Richard Rodgers Songbook, his ninth album, came out on December 16, 2020, with the pianist Yuki Futami, the bassist Park Jin-gyo and the drummer Lee Seong-gu. It was nominated for Best Jazz Vocal Album at the 19th Korean Music Awards, held on March 1, 2022, alongside BuYoung Lee, the Golden Swing Band and the Korea Jazz Guardians; Maria Kim won. The same record gave its name to an "American Songbook" concert series: for his tenth debut anniversary he sang at the JCC Art Center in Daehangno, Seoul, on December 17, 2021, with the hall limiting itself to 86 seats because of distancing rules. In Jeonju, the Jeonbuk Ilbo reported on June 29, 2021 that he had opened a live hall, The Vine Hall (더바인홀) in the Samcheon-dong district, in March 2021 and would run a monthly series of jazz, classical and acoustic concerts from July. The first, on July 10, 2021, featured his quartet with the pianist Jaehun Kang, the bassist Park Jin-gyo, the drummer Lee Seong-gu and the saxophonist Song Ha-cheol, and the paper recorded his wish to help popularize jazz in Jeonju and his plan to pay for a small jazz festival himself in autumn 2022.

Candy: Memories of Nat King Cole Trio (October 19, 2022, billed to Kim Ju Hwan and His Trio) is his tenth regular album. It takes the piano, guitar and bass format of the Nat King Cole Trio, without drums, with Joon Smith on guitar and arrangements, Jaehun Kang on piano and Park Jin-gyo on bass; the singer is credited with production and with mixing and mastering at Johnny Company in Jeonju. He sings above Cole's original keys and with very little studio processing, and the MMJAZZ editor Kim Hee-jun wrote in January 2023 that it cost him more trial and error than any of his earlier records, with two complete sets of recordings thrown away. Newsis reported a concert at the Mapo Art Center on October 28, 2022, part of the Mapo Cultural Foundation's Jazz Reboot series, and quoted him saying that he wants to record 500 jazz standards before he dies. Candy was a nominee for Best Jazz Vocal Album at the 20th Korean Music Awards on March 5, 2023, which Yujin Kim won; the other nominees were Maria Kim, Song Yi Jeon with Vinicius Gomes and Youn Sun Nah.

From 2023 he released a run of singles, mostly on Laura Records through Biscuit Sound, among them "Comes Love", "That Old Feeling" and "April in Paris". After Midnight: Still in the Moonlight (November 11, 2024), his eleventh regular album, gathers ten standards sung to Futami's piano alone; six of its titles had already come out as singles. It was recorded by Kim Ji-min at Minor Swing Studio in Seoul and mixed and mastered by Kim himself at Johnny Company, and it was one of five nominees for Best Jazz, Vocal Album at the 22nd Korean Music Awards on February 27, 2025, won by Nam Yeji over Hae In Cho, Kim Min-hee and Youn Sun Nah. A reader review in Hankyung's arte section, dated January 3, 2025, praised a "Sings American Songbook" show by his band for its humorous stage talk and the skill of every player. For November 29, 2025 at Seongsu Art Hall in Seoul a Sinatra songbook concert was billed with a 19-piece big band that includes a nine-piece string ensemble, under the music director Choi Soo-jin (최수진), and the promoters said a twelfth album in homage to Frank Sinatra was in progress. The newest titles on the streaming services are singles, the latest being "Soul To Soul" (February 5, 2026), a slow, sorrowful piece with the pianist Heo Dae-wook (허대욱).

His name is spelled in several ways. Streaming services file him as Kim Ju Hwan, the cover of Close To You reads Ju Hwan Kim, the cover of My Funny Valentine Kim Ju-hwan, and the 2024 After Midnight cover and the credits of Jaehun Kang's 2025 album Mean What You Say use Juhwan Kim. His YouTube channel is titled Johnny Kim, and the Jeonju company credited on his releases is called Johnny Company.

Kim sings in the crooner tradition of Frank Sinatra, Tony Bennett and Nat King Cole, and the press keeps comparing him to those singers; Sports Kyunghyang's 2017 report contrasts him with young Korean players who follow modern New York jazz. His repertoire is the Great American Songbook, usually organized as songbooks: Cole Porter and Harold Arlen, Richard Rodgers, the Nat King Cole Trio. Critics have also noted a voice that is higher and softer than the classic baritone crooner: Choi Kyu-yong wrote in the liner essay for Warm Like Love that he concentrated on his mid-high register and conveyed warmth through intimacy rather than weight, and the release text for My Favorite Things compared his tone to Chet Baker's and his softness to Michael Bublé's. His own approach is to arrange standards to suit his voice and to stay close to the original ensembles, as on Candy, where the trio follows the Cole Trio's sound and the arrangements change little beyond tempo and introductions.

Not everything he records is strictly standards: Skyfall is a pop and film-music program in jazz arrangements, and he has released Korean-language singles such as "Tears Run Down" (눈물이 나, 2019) and "The Last Farewell" (마지막 인사, 2021). Press, the awards and his collaborators place him in jazz: the Korean Music Awards considered him in its jazz vocal and jazz categories on three occasions, and his rhythm sections are drawn from the Korean swing and bop scene.