Yoonji Kim's international career began after winning 2nd prize - when 1st was not awarded - at the Prague Spring Competition in the Czech Republic in 2011, which is only held every six years for piano. She has had further success by winning the Steinway Prize Berlin, the Chopin Special Prize at the Cologne International Music Competition, and a prize at the Councours Musical International Reine Elisabeth in Brussels. In her youth, she won numerous first prizes at music competitions, as well as 1st prize at the Korean Broadcasting System Music Competition (KBS), the most important national Korean competition. Studio productions and live recordings by radio and television stations document her versatility worldwide, as do her increasingly numerous appearances at major international festivals.
She has been euphorically acclaimed not only in many concerts with the top Korean ensemble KBS Philharmonic on concert tours in her home country, but also with several European orchestras such as the Prague Philharmonia Orchestra, the Belgian National Orchestra under conductors such as Charles Olivieri-Munroe and Marin Alsop.