Promoted to captain on February 1, 1971, Williams served operational tours in both the continental United States and the Republic of Vietnam before being ordered to the Marine Corps Amphibious Warfare School, Quantico, Virginia, in 1973.

Returning to the United States in the summer of 1975, Capt Williams joined Marine Helicopter Squadron 1 at Quantico.

He was promoted to major on August 1, 1977, and in July 1978, he was selected to attend the Marine Corps Command and Staff College, Quantico.

Naval Academy at Annapolis, Maryland, where he served as a company officer and executive assistant to the Commandant of Midshipmen.

BGen Williams served in that capacity until July 16, 1993, when he assumed command of 2nd Force Service Support Group (2nd FSSG).

On June 8, 1994, BGen Williams was appointed commanding general, Joint Task Force 160, a humanitarian relief effort for Haitian and Cuban migrants at Guantanamo Naval Base, Cuba.

LtGen Williams served as the deputy chief of staff, programs and resources, Headquarters, Marine Corps, Washington, D.C., as his last assignment prior to becoming the assistant commandant.