Ruud Zielhorst started his pianolessons at the age of zeven. Marlies van Gent prepaired him for his Bachelorstudies at the Royal Conservatoire of The Hague, where he studied with Ellen Corver. After finishing his Bachelorstudies, he continued his Masterstudies in Essen with Evgeny Sinaiski, Yannick Rafalimanana, Xaver Poncette and Henri Sigfridsson. In this Master he focussed on chambermusic, together with stringinstruments and singers. In 2016 Ruud was correpetitor in the dramalessons for singers at the Royal Conservatoire.

He won several prizes, at the Princes Christina Concours among others, and forms ensembles together with Nikolau Ratchev (violin), Skyste Diksaityte  (violin) Anna Maria Wunch (altviolin), Emily Wittbrodt (cello), Garwyn Linnell (cello), Molly Wreakes (horn), Vera Fiselier and Emily Dilewski (song and opera).

Together with Maria Fiselier (mezzo-soprano) he recorded songs by Mattheu Dijker for the CD ‘The Madness of this World/De Waanzin van deze Wereld’.

He was pianist in the National Youth Orchestra, the Nieuw Kamer Orkest and in Ensemble Royaal. He also played together with several choires, like Kamerkoor Ad Parnassum, het Nederlands Zangtheater and Kamerkoor Kwintessens.

He participated in masterclasses by Tatiana Zelikman, Igor Roma, Nata Tsevereli and Paul Komen and had lessons with Naum Grubert and Paulo Giacometti.