Crist was commissioned a second lieutenant in the U.S. Marine Corps in 1952. While a lieutenant, he served in all three active duty Marine divisions. During the Korean War, he served with the 1st Marine Division in Korea.
By 1963, Crist had returned to the 2nd Marine Division, where he deployed with an infantry battalion to the Caribbean during the 1962 Cuban Missile Crisis. Later, as Assistant Division G-3, he completed airborne training at Fort Benning.
His first tour in Vietnam came in 1965. As an advisor to the Vietnamese Joint General Staff, he participated in combat operations throughout the Republic of Vietnam.
When he returned to the U.S., he spent three years at Headquarters Marine Corps in Plans and Programs. While in Washington, he was promoted to colonel.
In the summer of 1975, Crist was ordered to Headquarters, Fleet Marine Force (FMF), Atlantic, Norfolk, Virginia, where he served as Assistant Chief of Staff, G-3, Chief of Staff, and following his promotion to brigadier general, as Deputy Commander.
In 1978, he was transferred to Europe as the deputy director of Operations (J-3), U.S. European Command, where he was actively involved in a series of crisis actions ranging from Iran to Africa.
In 1980, Crist was promoted to major general and returned to the United States as the Deputy Chief of Staff for Reserve Affairs. This was followed two years later by a tour with the Joint Chiefs of Staff as the Vice Director, Joint Staff. On Oct. 23, 1983, during a weekend of international crises at the White House, Crist was secretly dispatched from Washington to assist six Caribbean states organize a 300-man Caribbean Peace Force to support the surprise, U.S.-led invasion of Grenada on Oct. 25. For the next five days, Crist served as the on-scene military liaison between the regional peacekeepers and the White House, the Pentagon, the State Department and the CIA.[3] After his return to Washington, Crist on Nov. 2 testified before a Congressional subcommittee on the weapons that were captured from Cubans and Grenadians by American troops in the course of the eight days of hostilities.[4]
In 1984, he was promoted to the rank of lieutenant general and served as the Deputy Chief of Staff for Installations and Logistics and Quartermaster General and then as Chief of Staff, Headquarters Marine Corps.
Crist was promoted to the grade of general in November 1985—the first active-duty Marine to achieve that rank without serving as Commandant or Assistant Commandant of the Corps—and on November 27, 1985, he assumed command of the U.S. Central Command (CENTCOM), MacDill Air Force Base, Florida. At CENTCOM, he helped to run Operation Earnest Will, the escort of reflagged Kuwaiti tankers; Operation Prime Chance, the secret actions against Iranian naval forces; and Operation Praying Mantis, the April 18, 1988, retaliation for the Iranian mining of the USS Samuel B. Roberts.
General Crist retired from active duty in December 1988 after more than 36 years of service. Following retirement, he became a military consultant for CBS news in 1990, appearing on national television and radio throughout the Gulf War and during subsequent crises in Africa and the Middle East.
The general and his wife Barbara moved to Beaufort, South Carolina, in 1990 after they restored an old house in the Historic District
He has earned a BA, cum laude, from Villanova University, an MS in political science from Auburn University, and was awarded an honorary Doctor of Military Science[5] by Villanova University.
^Register of Commissioned and Warrant Officers of the United States Navy and Marine Corps and Reserve Officers on Active Duty. Bureau of Naval Personnel. January 1, 1965. p. 856.