Born in Hong Kong to Swiss and American parents, Theodor grew up in New York and Switzerland before moving to the UK to attend Cambridge University and the Royal Academy of Music. Whilst at Cambridge, he held prominent positions in various ensembles including the university's Symphony, Chamber, and Opera Society Orchestras, and was named Cambridge University Symphony Orchestra's Principal Conductor during the academic year of 2011-12. Upon graduating he was awarded the Donald Wort Award (for Greatest Proficiency in a Final Recital) and the Royalton Kisch Prize for Music (for the highest final examination mark of his college). He then moved to London to pursue a Masters degree at the RAM where he studied violin with Maurice Hasson and conducting with Ray Holden, received additional coaching from members of the Britten Sinfonia, the BBC Philharmonic and the Royal Liverpool Philharmonic, performed in masterclasses for Maxim Vengerov and Levon Chillingirian, and played as a section principal or co-principal for many distinguished conductors including Semyon Bychkov, Christophe von Dohnanyi, Edward Gardner, Thierry Fischer, and Jane Glover.
Theodor graduated from the Academy with Distinction in 2014 and has since shared the stage with some of the world's most exciting artists including Zubin Mehta, Valery Gerghiev, Ivan Fischer, Esa-Pekka Salonen, Antonio Pappano, Leonidas Kavakos, Pinchas Zukerman, Renaud Capuçon, Janine Jansen, and many others. He is a founding member of the Cardinal String Quartet, Rotating Principal Violin II of United Strings of Europe, and Deputy Principal Violin II with the English National Ballet Philharmonic. He’s been featured as a concerto soloist with the Ensemble Eroica, Silk Street Sinfonia, and Cambridge University Symphony Orchestra, and has performed as section principal/sub-principal with Welsh National Opera, the Royal Philharmonic Orchestra, Royal Northern Sinfonia, and the City of Birmingham Symphony Orchestra. He currently plays an 1865 Baldantoni generously lent to him by the Harrison-Frank Foundation.
When not making music, Theodor enjoys writing and has received accolades for both his poetry (Strokestown International Poetry Festival) and his prose (1000 Word Quarterly). He published his first novel, The Winter Wilds, in 2020.