Maazel was born to American parents in Neuilly-sur-Seine in France and brought up in the United States. He was something of a prodigy, taking his first conducting lesson at age seven and making his debut at age eight. At twelve he toured America to conduct major orchestras. He made his violin debut at the age of fifteen. He later studied at the University of Pittsburgh.

In 1960 he became the first American to conduct at Bayreuth. He was conductor of the Deutsche Oper Berlin from 1965 to 1971 and the Berlin Radio Symphony Orchestra from 1965 to 1975.

In 1972 he was chosen to succeed George Szell as Musical Director at the Cleveland Orchestra. He was strongly opposed by the orchestra's musicians, who felt left out of negotiations; in a straw poll only 2 of 100 members found him to be the best choice. Maazel's emotional, rich interpretation of music greatly differed from Szell's characteristic crisp, defined precision in performance. He held the post until his departure in 1982. His most significant undertaking during this time was the first complete recording of George Gershwin's Porgy and Bess, which used an entirely African-American cast.

Following Cleveland, Maazel served at the Vienna State Opera from 1982 to 1984, the Pittsburgh Symphony Orchestra from 1988 to 1996, and the Bavarian Radio Symphony Orchestra in Munich from 1993 to 2002. In 2002 he succeeded Kurt Masur as music director of the New York Philharmonic Orchestra.

In March 2006, Lorin Maazel toured Asia with violinist Lidia Baich, conducting orchestras such as the famous Singapore Symphony Orchestra.