Leonard F. Chapman Jr., 86, a retired general and former commandant of the Marine Corps who supervised the corps' withdrawal from the Vietnam War and led it through a period of heightened social and racial tensions, died of cancer Jan. 6 at Inova Fairfax Hospital.

After his military retirement, Gen. Chapman became head of the U.S. Immigration and Naturalization Service.

Gen. Chapman, an artillery officer by training, served aboard a Navy cruiser and with Marine landing forces in the Pacific in World War II. He subsequently had several assignments in Washington, where he gained a reputation for cool efficiency. He was assistant commandant of the Marine Corps when President Lyndon B. Johnson passed over two better-known officers who had been touted for the job and appointed him commandant. He took over Jan. 1, 1968.

Within weeks, the communists launched the Tet Offensive across South Vietnam. Marines were heavily engaged in the battle for Hue and in the siege of Khe Sanh near the demilitarized zone between North and South Vietnam.

As disenchantment with the war spread, Marine ground forces began to be withdrawn. Under Gen. Chapman's direction, the process was completed in 1971. His slogan was, "Don't leave anything behind worth more than five dollars."

During the same period, drug and alcohol abuse became serious problems within The Corps, and long-simmering racial tensions broke into the open, mirroring developments in the society at large. There were fights between black and white Marines at enlisted clubs on many bases, and in the summer of 1969 there was a near riot at Camp Lejeune, N.C. In February 1970, someone in a group of blacks threw a hand grenade into a service club in Vietnam. One person was killed and 62 were injured.

Gen. Chapman responded with a combination of discipline and a broad range of programs designed to recognize black cultural symbols, promote understanding between the races and eliminate discrimination in assignments and promotions.

In his widely praised history of the Marine Corps, Allen R. Millett said, "The greatest difficulty proved to be convincing officers and NCOs that they would have to take positive action to stop interracial tension and allay fears of black Marines that they would be victimized by 'The Man.' "

Despite what Millett described as "deep-seated racial hostility in the ranks," progress was apparent by the time Gen. Chapman retired as commandant Dec. 31, 1971.

"He was a gentleman and a leader,' " said Gen. James L. Jones, the current Marine commandant, on Gen. Chapman's death. "He epitomized everything it means to be called a Marine. He guided our Corps through turbulent times, demobilization and the ultimate recovery from the Vietnam years. His many contributions kept the Marine Corps on the right path and brought us to where we are today."

Gen. Chapman was a native of Key West, Fla., and graduated from the University of Florida. He entered the Marine Corps through the Reserve Officers' Training Corps and was commissioned in 1935. One of his early assignments was to attend the Army artillery school at Fort Sill, Okla.

Early in World War II, he commanded the Marine detachment aboard the cruiser Astoria and took part in the Coral Sea and Midway battles, both of which were important U.S. victories. He later served in an artillery regiment in the 1st Marine Division and took part in the bitter fighting for Peleliu and Okinawa.

Gen. Chapman's later career included command of the Marine Barracks at Eighth and I streets SE and several tours of duty at Marine Corps headquarters.

After the general's retirement from the service, President Richard M. Nixon appointed him commissioner of the INS, where he served from 1973 to 1976. He lived in Alexandria.

Gen. Chapman's military decorations included three awards of the Distinguished Service Medal, two awards of the Legion of Merit, one with combat V, and the Bronze Star and Navy Commendation Medal, both with combat V.

His wife, Emily Chapman, died in 1992. A son, Leonard F. Chapman III, died in 1979.

Survivors include a son, Walton Chapman of Shelburne Falls, Mass., and a granddaughter.