He studied the violin with his father (principal viola at the Théâtre de la Monnaie in Brussels and later of the Metropolitan Opera Orchestra), and later with Édouard Deru, Pierre Henrotte and Eugène Ysaÿe. He joined the New York Philharmonic in 1919 as a violinist and was appointed first viola in 1925, a position he retained until 1929, collaborating in those years with Willem Mengelberg, Wilhelm Furtwängler and Arturo Toscanini. It was at Toscanini's encouragement that he began his conducting career.
He received violin lessons from his father (principal violist of the Théâtre de la Monnaie in Brussels and later of the Metropolitan Opera Orchestra), as well as Édouard Deru, Pierre Henrotte, and Eugène Ysaÿe. He became a member of the New York Philharmonic in 1919 as a violinist and was appointed first viola in 1925, a position he held until 1929, working alongside Willem Mengelberg, Wilhelm Furtwängler, and Arturo Toscanini. It was Toscanini who inspired him to start his career as a conductor.