Tantawy, who is of Nubian origin, joined the Egyptian Military Academy in 1952 and received his commission as an Army officer on 1 April 1955 in the infantry. The following year he took part in the Suez War (or the Tripartite Aggression as it is often known in Egypt) as an infantry platoon commander. He was promoted to Major in 1961 and commanded an infantry company in Yemen during the North Yemen Civil War. Later in his career he was involved in the Six-Day War of 1967 as a battalion commander, the War of Attrition of 1967–1970, and the October or "Yom Kippur" War of 1973. During the Yom Kippur War he was a Lieutenant Colonel commanding the 16th mechanized infantry battalion. He held various command and staff appointments including both the Chief of Staff and then Commander of the Second Field Army between 1986 and 1989. Additionally he has served as a military attaché to Pakistan between 1983 and 1985, an important role given the two countries' political and military links. Tantawy served as a Commander of the Republican Guard Forces between 1989 and 1991, and later a Chief of the Operations Authority of the Armed Forces. In 1991, he also commanded an Egyptian Army unit in the U.S.-led Gulf War against Iraq to force Iraq to withdraw from Kuwait, which it had invaded in 1990.