Moon Landrieu was born in uptown New Orleans.
Landrieu received a BBA from Loyola University of New Orleans in 1952 and his law degree from Loyola in 1954. After a three year stint in the United States Army, Landrieu opened a law practice and taught accounting at Loyola.
In 1960 Moon Landrieu was elected by the 12th Ward of New Orleans to the Louisiana State House of Representatives. There he was one of the few white legislators who voted against the "hate bills" of the retreating segregationists which the legislature passed in the effort to thwart the desegregation of public facilities and public schools.
In 1966 Landrieu was elected Councilman-at-large of the New Orleans City Council. In 1969 he led a successful push for a city ordinance outlawing segregation based on race or religion in public accommodations.
Moon Landrieu was elected Mayor of New Orleans in 1970, and reelected in 1974, serving until April of 1978. During his tenure he oversaw desegregation of city government and public facilities. He was also involved in the planning and construction of the Superdome and other projects designed to improve the economy of New Orleans.
During 1975-1976 Landrieu also served as president of the United States Conference of Mayors.
Landrieu served as Secretary of the United States Department of Housing and Urban Development (HUD) during President Jimmy Carter's administration.
Landrieu served as Judge of the 4th Circuit Court of Appeals from 1991 until his retirement in 2000.
Moon Landrieu is father of Senator Mary Landrieu.