Orchestre de la Société des Concerts du Conservatoire
In 1937 he joined the Boston Symphony Orchestra under Serge Koussevitsky, performing as first cellist until 1940. In 1938 he began a solo career at Boston's Town Hall, accompanied by Leonard Shure. He was first cellist of the Orchestre de la Société des Concerts du Conservatoire, Paris, 1946–47. In 1947 he gave his British debut under Beecham, again performing "Don Quixote" at the Festival of Richard Strauss in London. "My boy", Beecham said, "you will be successful in England because you have temperament". In 1950 Tortelier was selected by Pablo Casals to play as the principal cellist in the Prades Festival Orchestra. Tortelier believed that of all the cellists, it was Casals who influenced him the most. A French critic wrote of him: "If Casals is Jupiter, then Tortelier is Apollo." Tortelier performed for the Peabody Mason Concert series in Boston in 1952.