Blanken graduated from the Conservatoire of Amsterdam, as a student of Baslawskaja and Austbø. In 2002 Jelger won the prestigious Medal of the Friends of the Concertgebouw.
As a chamber musician he performed with internationally renowned musicians such as Nobuko Imai, Philippe Graffin, David Waterman and Raphael Wallfisch. Blanken performed at many international festivals, such as the Franz Liszt Festival in Utrecht, International Chamber Music Festival Schiermonnikoog, Grachtenfestival in Amsterdam, Enghien International Musical Encounters (Belgium) and Rovigo cello city Festival (with Floris Mijnders). He also took part in the chamber music series of the Royal Concertgebouw Orchestra, Rotterdam Philharmonic Orchestra and the Munich Philharmonic Orchestra.
In 2010 Jelger performed several pieces by Dutch composers in the Rotterdam Gergiev Festival, together with violinist Philippe Graffin. Most of these pieces were recorded on CD for Onyx Classic. His playing received high praise from music magazines such as Gramophone, The Strad and the International Record Review.
Jelger Blanken is an instrumental coach and accompanist at the Royal Conservatoire in The Hague. He also earned his Master’s degree in Art and Cultural Sciences from the Erasmus University in Rotterdam.