Dejan Kušer first began playing the diatonic accordion, which he still plays today. His mentor was Brane Klavžar. Among other achievements, he won the Golden Accordion of Ljubečna competition in 2004, which was once considered the most prestigious contest for this instrument. Later, he switched from the diatonic to the piano accordion and, during his studies at the secondary music school, to the button accordion. He gained knowledge from numerous top Slovenian and international music educators, including Tomaž Guček, Luka Juhart, Primož Parovel, and Klemen Leben.

He completed his master’s degree at the Ljubljana Academy of Music and collaborated with various chamber ensembles, especially valuing those under the mentorship of Professor Tomaž Lorenz. As an accordion teacher, he now passes on his musical knowledge to younger generations at both the elementary and secondary music schools in Celje, and, as of this year, also in Ljubljana.

Until 2023, Dejan Kušer was a member of the duo Accordion Clash, in which he and Miha Debevec combined the sounds of the classical and diatonic accordions. Among their most notable recent performances were concerts in New York, Brussels, Berlin, Stockholm, Florida, and Texas. The duo developed a distinctive musical expression, marked by emotive interpretation and virtuosic mastery of their instruments. Their music often transcended traditional boundaries, entering genres typically considered demanding for these two types of accordions.

As a solo performer, Dejan enjoys including works in his repertoire that are rarely played on the accordion—or in some cases, never before performed on it.