Blanchard was born on April 3, 1920 in Washington, D.C. and graduated in 1938 from Eastern High School. After high school he attended American University from 1938 to 1940, then enlisted in the National Guard, serving in the Coast Artillery and rising to the rank of sergeant. He received a National Guard appointment to the United States Military Academy and graduated on D-Day, June 6, 1944. He was commissioned in the infantry, and was soon deployed to Europe, serving with the 70th and 78th Infantry Divisions. After World War II, he served on the general staff of United States Forces, European Theater, and then returned to the states to earn a Master of Science degree in Public Administration from the Maxwell Graduate School of Citizenship and Public Affairs at Syracuse University in 1949. Blanchard served in various positions during the 1950s, including as an assistant to the Chairman of the Joint Chiefs of Staff, General Omar Bradley, a tactics instructor at Fort Benning; and as a military advisor in Taiwan from 1955 to 1957. After being promoted to colonel in 1959, Blanchard assumed command of the 2nd Airborne Battle Group, 503rd Infantry, 82nd Airborne Division, and subsequently served as the G-3 of I Corps in Korea. In 1966, he went to Vietnam and served as Assistant Division Commander, 1st Cavalry Division, and later served as Chief of Staff, I Field Force, Vietnam. After his time in Vietnam, he was assigned as Director of Special Warfare in the Office of the Deputy Chief of Staff for Military Operations; and Director of Plans, Programs and Budget for two major Army General Staff organizations, and he served as executive officer to two Secretaries of the Army. After his time at the Pentagon, he took command of the 82nd Airborne Division in 1970. He next returned to Europe to command the VII Corps, and subsequently U.S. Army Europe, as the army was transitioning to an all-volunteer force. He is credited with instituting the use of television to broadcast command information. He also instituted the Sergeant Morales competition in 1973, a program to designed to improve the morale and performance of the NCO corps. Blanchard was also known for his attempts to combat alcoholism in the army, which included banning discount drinks during happy hours in post clubs, prohibiting units from holding drinking contests, and opening the first alcoholism treatment center in Europe for officers and senior enlisted soldiers.
Blanchard retired to McLean, Virginia, where he established General Analysis Inc., a defense consulting firm. He was also a member of the Atlantic Council Board, the Army Science Board, the Washington Institute of Foreign Affairs and president of both the Retired Officers Association and the United Service Organizations in the 1980s. In 1990, the Blanchards moved to North Carolina, and while there he helped organize a program where retirees tutor the illiterate. In 2001, the Association of Graduates, the United States Military Academy alumni organization, selected him as that year's recipient of the Distinguished Graduate Award. He and his wife returned to Virginia in 2002 to live at The Fairfax, a military retirement community in Fort Belvoir. Blanchard died of pneumonia on May 3, 2006 at Inova Mount Vernon Hospital at the age of 86. At the time of his death he was survived by his wife Beth H. Blanchard, four daughters, eight grandchildren, and three great-grandchildren.