After completing his high school education in South Korea, Kim continued his studies at the Giuseppe Verdi Conservatory in Milan, Italy, graduating with a perfect score with honors (Dieci e lode e menzione) in 2010.

[21] He has since portrayed leading roles in various renowned operas, including La traviata, The marriage of Figaro, Madama Butterfly, Cavalleria rusticana, Cosi fan tutte, Il barbiere di Siviglia, Simon Boccanegra, Il signor Bruschino, Das Rheingold, Lucia di Lammermoor, La bohème, and Rigoletto across multiple theaters in Italy.

This renowned theater, known for hosting premieres of works by eminent composers including Rossini, Bellini, and Donizetti, holds a special place in the history of Italian opera.

Especially, Julian Kim has portrayed the character Figaro[23] during the 2014–2020 season at Teatro La Fenice, featuring in 47 out of a total of 60 performances of Il barbiere de Serville.

Ludwig van Beethoven Vincenzo Bellini Gaetano Donizetti Pietro Mascagni Wolfgang Amadeus Mozart Giacomo Puccini Gioachino Rossini Giuseppe Verdi Richard Wagner

Phantom Singer is a television show on JTBC in Korea that functions as an audition program to select a male crossover vocal quartet.

Julian Jootaek Kim mentioned feeling his heart race while watching Phantom Singer 1, leading to a realization that he needed a change in his life.

His colleagues in the classical field, as well as his parents, were worried that his exposure to popular music could harm his career in opera when he decided to participate in Phantom Singer 2.

During the COVID-19 quarantine period, JTBC aired a program called Phantom Singer All Stars, where the three finalist quartet teams from the previous three seasons competed or showcased their performances to online audiences.

Miraclass excelled in this show, securing numerous wins, including one MVP by performing a rendition of Josh Groban's song "Mai,"[105] in the competitions among the nine participating groups.

Since their formation on September 26, 2017, Miraclass has actively hosted concerts, released full albums, and engaged with their audience through a YouTube channel named Just-10-minute produced by mexicomini52.

In concert adaptations of Das Rheingold under the baton of Myung-whun Chung in Seoul in 2014,[117] and Fidelio conducted by Sir Antonio Pappano in Rome in 2016,[118] Kim assumed the roles of Donner and Don Fernando, respectively.

[125] This recital featured a diverse range of pieces, including works by composers like F. Schubert, J. P. E. Martini, G. Giordani, F. P. Tosti, S. Gastaldon, and F. Chopin, alongside arias from Lucia di Lammermoor and L'elisir d'amore by G. Donizetti, Don Giovanni by W. A. Mozart, and Giovanna d'Arco and La Forza del Destino by G.

[132] This initiative aimed to bring a variety of cultural performances to stages in smaller cities and rural areas across Korea, with a focus on including at least 30% of underprivileged individuals in the audience.

[133] Kim, along with his Miraclass teammate Tenor Phillip Jeong, magician Hyungbae Choi, Soprano Veronica Yoo, and the BeHa Philharmonic Orchestra, actively participated in the program.

[134] Traveling to 10 cities throughout Korea in 2022 and 2023, this interdisciplinary team showcased a mix of opera arias, Korean lyric songs, Spanish and Italian melodies, musical numbers with orchestral accompaniment, and magic acts.

[196] He also received acclaim for his richly resonant operatic voice, and additional praise came for his adept portrayal of the Phantom, which skillfully balanced strength and sensitivity, leveraging the inherent flexibility.

[199] He demonstrated impressive vocal skills and subtle acting while portraying Pierre, a character from a Russian aristocratic background, who embodies a melancholic demeanor and struggles to fit into upper-class society.

[200] Considered as a newcomer with tremendous talent, Kim made a significant impact with his portrayal, which was reviewed as having solid vocal power and nuanced acting, and he played the accordion and piano in the show while singing.

[203] In contrast to the hundreds of classical vocalists graduating from colleges in South Korea every year, the opportunities for them to perform on stages within the country are notably scarce.

[247] The program strived to offer an accessible exploration of opera by discussing overviews and backgrounds of arias, accompanied by live piano performances by Taeyang Jeong while the vocalists sang.

'[282] Since Kim made his opera debut performing Il barbiere di Siviglia, he has portrayed the character of Figaro in the production 75 times across various cities in Italy.

Continuous performance opportunities as Figaro, who needed to sing "Largo al factotum" full of rap-like tongue twisters, were the assurance of his success as an opera singer in Italy.

Reviews of his Figaro performance stated: 'Julian Kim is Figaro: the Korean baritone would perhaps be more at ease in singing parts; the diction was not always exact, but the high notes were beautiful, the accent was lively, and the color of the voice remained beautiful,'[287] 'The artistic direction, spearheaded by Cristiano Sandri, made unexpected choices in forming an excellent cast, well blended in terms of both vocal quality and stage presence.

'[289] Fidelio, the sole opera composed by Ludwig van Beethoven, was presented in Rome's Sala Santa Cecilia in Parco della Musica, conducted by Sir Antonio Pappano[168] in 2016.

The critiques highlight: 'Excellent performance by Julian Kim (Posa), who possesses a remarkable voice, characterized by its dark timbre and skilled modulation between forte and piano.

'[296] They also stated: 'Among the performers, the most Verdian voice, exemplifying weight and solidity, belongs to baritone Julian Kim, notable for his portrayal as the Marquis of Posa, a role that received substantial directorial attention.

His well-supported singing voice, with its appealing timbre, coupled with secure phrasing enriched by subtle accents, added depth to his character portrayal.

He captured the Phantom's intense fixation on Christine and portrayed the character's madness effectively with his explosive vocal presence and compelling energy that filled the venue,’[297] and 'Baritone Julian Jootaek Kim, venturing into a musical for the first time, captivated audiences from his initial performance with his rich voice.

[274] Gianni Tangucci, serving as a judge for the Zandonai International Competition, played a significant role in Julian Jootaek Kim's career by casting him in his opera debut as Figaro in Il barbiere di Siviglia at the Teatro Pergolesi.