 His ability came to the attention of the famed Arturo Toscanini, who had become principal conductor at the Met in 1908, and Pasternack was made assistant conductor in 1909, a position he filled for one year.In 1911 he returned to Europe as conductor of the Bremen Opera, but the Metropolitan asked for his release and he returned to the Met as a conductor for 1911-13.During the period 1913-26, he was conductor of the Century Opera Company in New York, the Chicago Symphony Orchestra, the Boston Symphony Orchestra, and the Philadelphia Philharmonic Society.