Ismail graduated from the Cairo Military Academy in 1938, saw service with the Allies in the Western Desert during World War II, and fought as a brigade commander in the first Arab-Israeli war (1948–49). He later trained in Britain, fought the Franco-British-Israeli forces during the Suez operation of 1956, undertook further training in the Soviet Union, and was a divisional commander in the Six-Day War of 1967. He was made chief of state in March 1969, but was dismissed by President Gamal Abdel Nasser in September as a scapegoat for successful Israeli raids. New president Anwar al-Sadat, however, named him chief of intelligence in September 1970. In October 1972, he accompanied Prime Minister Aziz Sidqi on a visit to Moscow and on his return stifled a coup against the president. That same month, he replaced the anti-Soviet general Muhammad Sadeq as minister of defense and commander in chief and was promoted to full general.
His skill as a strategist and his success in reviving the morale of the Egyptian army became evident in the October 1973 war. Isma'il was made a field marshal in November 1973.
Ismail died in December 1974 from advanced cancer.