In 1948 he took second prize in the Philadelphia Orchestra
's young conductor's contest. He took a job as organist of the Greenwich Village Presbyterian Church in New York. He and group of other young musicians formed a group called the Lemonade Opera Company, which he conducted for several years.
Schippers began conducting Menotti
's opera The Consul on Broadway shortly after its 1950 premiere. This began a strong association with Menotti
and with Samuel Barber
, which led to Schippers conducting the premiere performance of Menotti
's short Christmas opera Amahl and the Night Visitors, the first opera commissioned especially for television broadcast, on the NBC network on December 24, 1951. On April 9, 1952, he conducted Menotti
's The Old Maid and the Thief at the New York City Opera and remained on that company's conducting roster into 1954. He made his first appearances with the New York Philharmonic Orchestra, at La Scala in Milan, Italy, and at the Metropolitan Opera in 1955. With Menotti
, he was instrumental in organizing the Festival of Two Worlds in Spoleto, Italy, and was its first Music Director. He frequently guest conducted the New York Philharmonic Orchestra and made some classic recordings of music of Samuel Barber
with them. When the orchestra made its historic tour of the Soviet Union under Leonard Bernstein
in 1959, Schippers also went as its alternate conductor. It was he who was conducting at the Metropolitan Opera on March 4, 1960, when baritone Leonard Warren
died on stage. In 1962 he conducted the world premiere of Manuel de Falla
's cantata Atlantida. In 1964 Schippers made his first appearance conducting at the Bayreuth Festival. The Metropolitan Opera called upon him to lead the world premiere of Barber
's Antony and Cleopatra, which opened its new house in Lincoln Center in 1966. In 1970, Schippers accepted the position of music director of the Cincinnati Symphony Orchestra
, becoming one of the few American-born conductors to hold such a post at a major American orchestra at the time. He also became a faculty member at the University of Cincinnati College-Conservatory of Music in 1972.
Schippers' wife died of cancer in 1973. He was struck by lung cancer and unable to open the Cincinnati Orchestra
's season in 1977. The management gave him the title of conductor laureate. He died before the year was over, bequeathing the orchestra five million dollars.