 In 1925, soon after his graduation from the conservatory at 19, he joined the Kolisch Quartet.Lehner was a violist with the Kolisch Quartet from 1926 until 1939, performed with the Boston Symphony Orchestra for 39 years (the only player to be invited to join without an audition by Serge Koussevitzky), and continued teaching chamber music at the New England Conservatory of Music and Boston University well into his retirement.Late in his life most coachings were given at his home in Newton.