Joon-Sung Jun began playing cello at age 12. At age 16 he already began to perform with major orchestras in his homeland. He was accepted to the Idyllwild School of Music and the Arts in California with scholarship, and started his studies with Professor Eleonore Schoenfeld. During there years he was asked several times to return for concerts in Korea.

Joon-Sung Jun has invited to be a Chair Person of Instrument and cello professor in the Shepherd University School of Music in the year of 2000. He teaches and lectures in chamber music ensemble and literature. As a cello professor, he has numbers of cello students, and they have won 1st prize in competitions such as, Los Angeles Violoncello Society Competition, Collaboration Classical Competition, South Coast Symphony Concerto Competition, Marina Del Ray-Westchester Symphony Young Artist Competition, Brentwood Westwood Symphony Young Artist Competition, PSYO Concerto Competition and numbers of orchestra auditions. His students also have been accepted prestigious colleges such as Juilliard, Manhattan School of Music, Yale, UCLA, and USC. In his home land, South Korea, he has a contract to be a soloist and give Master Classes with the Prestige Youth Orchestra as their principal professor through out the country every year. During the summer seasons, he is invited to teach master classes at the An Dong University Summer Festival, Dong I University Summer Festival, Kazakhstan International Music Festival.

Joon-Sung is regularly invited as a featured soloist from the LA Dominant Club, Mu Phi Epsilon, LA Violoncello Society, Uol San Symphony, Ma San Symphony, Pusan Symphony, Korean Philharmonic, KAMF Orchestra, Catholic Boys Town, and Kazakhstan National Philharmonic, and he is invited from France, Paris conservatory to do String Quartet concert tour throughout France.

Under the guidance of Professor Schoenfeld, Joon-Sung Jun has received the BM and MM degree as a full Scholarship Honor Student at the University of Southern California, and now, he is pursuing the DMA degree.