The event was contested by musicians from 18 countries.
In addition to a cash prize, he was offered the chance to record an album in Germany next year.
Born in 1995 in Koszalin, northern Poland, Kowalski has a number of international successes to his name, including the top award at the EuroStrings International Guitar Competition in London in 2019.
His discography includes several albums, both as a soloist and chamber musician.
He has achieved particular reputation for his historically-informed interpretations of music across different periods.
Kowalski also pursues a teaching career as a faculty member of the Fryderyk Chopin University of Music in Warsaw.
(mk/gs)