Masur studied cello and piano while at the Breslau Music School from 1942 to 1944. After the war he found himself in the Soviet-occupied zone of Germany, which became the German Democratic Republic (DDR) or East Germany. His education then continued at the Leipzig Hochschule für Musik, where he studied piano, composition, and conducting (1946-1948). His professional career began as a coach and assistant conductor in the Halle Landestheater. He then became Kapellmeister of the Erfurt City Theater (1951-1953). Next, he was his appointed as Kapellmeister of the Leipzig Opera Theater. (1953-1955).
His first orchestral position came with the Dresden Philharmonic (1955-1958). He then returned to opera, becoming Generalmusikdirektor of the Mecklenburg State Theater in Schwerin (1958-1960). One of his most important appointments came in 1960, when he took the post as Senior Director of Music at the Berlin Komische Oper, where he worked with the famous director and producer Walter Felsenstein. He returned to the Dresden Philharmonic as its music director (1967-1972). In 1970 he became Gewandhauskapellmeister of Leipzig, a position of high prestige ever since the Gewandhaus Orchestra had been led by Wilhelm Furtwängler, Bruno Walter, and indeed Felix Mendelssohn. He remained at the Gewandhaus through 1996, during one of the most important stretches in the orchestra's history. Together they made numerous recordings for the East German state recording company, many of which became generally available in the West only during the 1990s. He also took the orchestra on significant foreign tours, and in 1975 he became a professor at the Leipzig Academy. Masur was a frequent guest conductor with the world's leading orchestras. His U.S. debut came in 1974, when he led the Cleveland Orchestra and also took the Gewandhaus Orchestra on its first American tour. His New York Philharmonic debut took place in 1981.
Masur became outspoken in his opposition to DDR policies, and in 1989 he played a central role in the growing demonstrations against Communist rule. As a result he was awarded several of Germany's highest civilian honors, and his profile in the West was raised still further.
In 1991 Masur was appointed music director of the New York Philharmonic. Although the orchestra was in fine form when he took it, he was been credited with sharpening its precision, creating a more incisive sound. Masur and the Philharmonic recorded extensively on the Teldec label. Under his tenure, the orchestra resumed its historic series of live national radio broadcasts, becoming the only orchestra in the United States with such a program in place. In 1999, the orchestra's "Messages for the Millennium" project commissioned works by Thomas Ades, John Corigliano, Hans Werner Henze, Giya Kancheli, and Kaija Saariaho, and in June of the following year, Masur and the Philharmonic completed their fifth European tour. In 1996 he stepped down from his position with the Gewandhaus, which elected to give him the title of Conductor Laureate -- the first time it had bestowed that honor. Since 1992, he held the lifetime title of Honorary Guest Conductor of the Israel Philharmonic Orchestra. In September 2000, Masur assumed the position of Principal Conductor of the London Philharmonic Orchestra, which he held until 2007. At the end of his contract with the New York Philharmonic in 2002, Masur became music director of the Orchestre National de France, a position he held until 2008. He remained active as a guest conductor for a few more years, although his age and health placed some limitations on his engagements.