Grynyuk was born in Kyiv, Ukraine, while the city was still part of the Soviet Union. He showed a strong interest in music as a child and gave his first concert at the age of six. Grynyuk took first prize at the Diaghilev All-Soviet-Union Piano Competition when he was 13; that was the first of several significant top prizes, including those at the Horowitz International Piano Competition in Kyiv and the Shanghai International Piano Competition in China. Grynyuk attended the Kyiv Conservatory, studying with Natalia Gridneva and Valery Kozlov. He went abroad for further work with Hamish Milne at the Royal Academy of Music in London and began to put down roots in British musical life; he was made Associate of the Royal Academy of Music and served on several prize juries. In 2013, he made his debut album on the Onyx Classics label, backing cellist Leonard Elschenbroich on an album of music by Shostakovich and Rachmaninov.
Grynyuk has often played chamber music, joining Elschenbroich and violinist Nicola Benedetti in a piano trio that has toured major venues such as London's Royal Albert Hall, the Alte Oper in Frankfurt, and the 92nd Street Y in New York. As a recitalist, he has been heard at Wigmore Hall in London, the Salle Cortot in Paris, the Great Hall of the Moscow Conservatory, and the Concertgebouw in Amsterdam, among other top halls. He is a consistent attraction at such festivals as the Verbier Music Festival in Switzerland, the Newport Music Festival in the U.S., and the Duszniki Chopin Festival in Poland. His repertory extends from the Classical period to the 20th century. Grynyuk recorded Liszt's Piano Sonata in B minor for the Orchid Classics label in 2013 and has made several more recordings with Elschenbroich, including Brahms Analogue (2022), which was recorded on analog equipment. ~ James Manheim, Rovi