Graduate of the Manhattan School of Music, piano student of Solomon Mikowsky (2011), awarded the Harold and Helen Schonberg Piano Scholarship (2007–11), established in memory of the long-time leading music critic of The New York Times. In 2013 he took up doctoral studies with Katarzyna Popowa-Zydroń and Jerzy Sulikowski at the Feliks Nowowiejski Academy of Music in Bydgoszcz, Poland.

Adam Kośmieja participated in piano masterclasses under Paul Badura-Skoda, Gary Graffman, Ivan Moravec, Andrei Gavrilov, Boris Berman, Mikhail Voskresensky, Lang Lang, Dina Yoffe, and had supplementary sessions with Arie Vardi, Dmitri Bashkirov, Ewa Pobłocka, and David Dubal. He took classes in composition with J. Mark Stambaugh and his violin, clarinet, and piano chamber trio was coached by David Krakauer.

He participated and gave concerts at many international piano festivals including Warsaw Autumn (2014), Gilmore (2012), Mózg International Contemporary Music Festival in Bydgoszcz (2013), Polish Piano Music Festival in Słupsk (2013), Les Journées Polonaises in Toulouse (2011), and International Piano Festivals in Spain (2010).

He won the 1st prizes in the Mieczysław Münz Piano Competition in New York (2009), Chopin Piano Competition at Columbia University (2010) and Josef Suk International Piano Competition in Prague (2013). He was also semifinalist at the 3rd China Shenzhen International Piano Concerto Competition.

Bydgoszcz is the home of a prominent chamber orchestra, Cappella Bydgostiensis, with which Adam Kośmieja made his concert debut at age eleven playing Mozart’s Piano Concerto in A Major K414.

He performs as a soloist in Europe, America, and Asia. In New York he performed at Carnegie Hall’s Weill Recital Hall and the Yamaha Concert Artist’s Hall. He has also given concerts in Japan, China, France, Spain, England, Sweden, Finland, Italy, and the Czech Republic.

His repertoire and performing experience range from the baroque up through contemporary music, including experimental music. Currently he is preparing a PhD on the complete piano music of Kazimierz Serocki (1922–81).

Other new music projects include 3xPiano (2009–11), which combines classical, jazz and electronic piano music, prepared in cooperation with American jazz pianist and 2014 Grammy nominee Christian Sands.

In 2014 Adam Kośmieja, together with Polish composer Stefan Węgłowski, created the contemporary music duet Kośmieja/ Węgłowski, focusing on reinterpreting the piano music of the Polish minimalist Tomasz Sikorski (1938–88) with the use of live electronics.