Rothstein co-led Yehudi Menuhin's Bath Festival Orchestra, the Boyd Neel Orchestra, and the Northern Sinfonia; he also led the Academy of St Martin in the Fields. As a conductor, Rothstein toured extensively with the Johann Strauss Orchestra and his own ensemble the Viennese Orchestra of London. For over 20 years, Rothstein was also a member of the London Czech Trio, in addition to other music ensembles, performing among others at The Dorchester and for the BBC.

Throughout his professional career, Rothstein also performed as a soloist, playing most of the well-known violin concertos with leading orchestras and giving solo recitals, appearing at the Royal Festival Hall and the Barbican Hall on various occasions.

In addition to his classical music career, Rothstein recorded many background tracks for film and television, including such British TV series as Birds of a Feather, The House of Elliot, Last of the Summer Wine, and Soldier, Soldier. He also played the violin on The Beatles songs "I Am the Walrus" and "Within You Without You".