Jung creates acoustic covers and arrangements, typically by ear and/or by watching videos, and composes original songs, both of which he plays and uploads online.

[4] His cover of "The Pirates of the Caribbean" theme song, which has over 61 million views on YouTube as of September 2020, made Jung an internet sensation.

[7] Jung has received guitar lessons from Hata Shuji, a well-known Japanese jazz guitarist.

He has also been mentored by German guitarist Ulli Bögershausen, who Jung has referred to as his musical inspiration,[8] and from whom he learned much about composing and arranging.

[13] Upon discovering Jung's skill with the toy-like guitar, his father decided to buy him a better one – a Cort Earth900.

His third guitar was a custom-made small-combo sized "All Spruce" Selma model, upon which Thomas Leeb wrote "KEEP ON GROOVING!

However, to make his songs better and more accurate, he occasionally spent from a couple of days up to a month practicing.

[16] In 2012 he collaborated with 2NE1, creating acoustic versions of the group's hit songs "Lonely" and "I Love You".

[23] Jung's fourth solo album, Monologue, almost exclusively composed of his own original pieces, was released on 28 April 2014.