Landau was born March 4, 1920 in Vienna, Austria and became a naturalized citizen of the United States in 1943. He attended Pace College and New York University and received his A.A. in 1969 from George Washington University. In May 1988 George Washington University awarded him an Honorary Degree as Doctor of Public Service. Landau entered the Army in November 1942. After graduating from Officer's Candidate School, he served as Military Intelligence Officer in the European Theater of Operations. He left active duty status as a Captain, Military Intelligence in 1947 but remained in the U.S.Army Reserve until 1975,when he retired with the rank of Colonel. Among his decorations are the Army Commendation Medal and the Meritorious Service Medal.
Landau served in private business as an executive of a shipping company (1947–55) and as general manager of an American automobile distributor in Colombia (1955–57). In 1957 he began his career in the Foreign Service as commercial attache and Chief of the Economic Section in Montevideo.'where he also served as member of the U.S. Delegation that created the "Alliance for Progress" at Punta del Este, Uruguay in 1961. From 1962 to 1965, he was political officer, then Deputy Chief of Mission in Madrid, and attended the Canadian National Defence College from 1965 to 1966. He was Country Director of the Office of Spanish and Portuguese Affairs, Bureau of European Affairs in the Department from 1966 to 1972. He was Ambassador to Paraguay (1972–77) and Ambassador to Chile (1977–82). From January to April 1982, he served as Executive Director of the Presidential Commission on Broadcasting to Cuba in the Department. President Ronald Reagan appointed him to be Ambassador to Venezuela in 1982. Landau received the State Department's Superior Honor Award for his work in the negotiation of the 1970 Spanish Base Agreement He also was the action officer in concluding the renewal of the Azores Basing agreement with Portugal in 1972. He was awarded the Presidential Meritorious Service Award in 1984 and has been decorated by the Governments of Argentina, Chile, Colombia, Paraguay, Peru and Venezuela. Ambassador Landau left the Foreign Service in 1985 to become President of the Council of the Americas and the Americas Society, the leading non-profit institutions devoted to strengthening business and cultural ties within the Hemisphere. He retired in 1993. Landau also served as Chairman of the Latin Advisory Boards of Coca-Cola and of Guardian Industries,a major float glass manufacturer with several plants in Latin America. He was on the Board of the Emigrant Savings Bank of New York from 1967 to 2005 and on the Advisory Committee of the Export-Import Bank in l991 and 1992. .Landau's foreign languages are German and Spanish. He is a member of the American Academy of Diplomacy and of the Council on Foreign Relations since 1983. He is a member of the Metropolitan Club of Washington, D.C. since 1983 and of the Mentropolitan Club of New York, since 1987 where he served as governor from 1991 to 1995. He is also a member of the American Foreign Service Association and of DACOR (Diplomatic and Consular Officers, Retired).