Colonel William M. Knarr, Jr. was commissioned as a Military Intelligence (MI) Officer upon graduation from Infantry Officer Candidate School class 4-73 on 19 July 1973. Prior to commissioning he was a staff sergeant.

Bill enlisted in the Army in 1967 and deployed to Vietnam in 1968. He was assigned to the 199th Light Infantry Brigade where he worked with a Vietnamese paramilitary unit under the Phoenix (CIA)/Phung Hoang (Vietnamese) Program. After returning home and an assignment to the 108th MI Group, Massachusetts, Bill completed the Army Counterintelligence Special Agent's Course at Fort Holabird, Maryland, in 1970. He was then assigned to the Fort Ritchie Field Office, Maryland, where he conducted security investigations to include a penetration operation to test Army installation security against domestic terrorism. In 1971-1972, he attended Mount Saint Mary's College, Maryland, and received his baccalaureate in mathematics. Bill attended OCS in 1973.

After commissioning, Lieutenant Knarr attended the Electronic Warfare Course at Fort Devens, Massachusetts, and then the rotary and fixed wing courses at Fort Rucker, Alabama, in 1974. His first operational assignment was as a flight section commander and then operations officer for the 120th Assault Helicopter Company, Fort Richardson, Alaska. He then activated and commanded the 452nd MI Detachment at Fort Richardson.

In Germany, from 1979-1983, Captain Knarr was with the 3rd Infantry Division. Initially he was the S2/Intelligence Officer, 3rd Aviation Battalion (Combat), in Kitzingen and flew the OH-58C helicopter. Then, he commanded the 851st Army Security Agency Company and transitioned it to A Company, 103rd MI Battalion in Wuerzburg. His last assignment with the battalion was as S3, Operations officer.

At Fort Rucker, U.S. Army Aviation Center, Alabama, from 1983 to 1986, Bill was the Electronic Warfare Officer, Directorate of Combat Developments, and later, the Chief of the Advanced Rotorcraft Technology Integration/ARTI Branch for the Light Helicopter Experimental/LHX program.

After Air Command and Staff College at Maxwell Air Force Base, Alabama, Bill served as the Aviation Signals Intelligence officer for a special operations unit in 1987. Next, he was the Chief, Intel/Ops Cell, U.S. Army Special Operations Agency, at the Pentagon. As a major he received the Legion of Merit for his work.

Bill commanded the 165th MI Battalion, Darmstadt, Germany, from 1992-1994. After the National War College in 1996, he was promoted to colonel and then activated/commanded the Joint Intelligence Center, U.S. Special Operations Command, MacDill Air Force Base, Florida. Next, as the TRADOC Systems Manager, Unmanned Aerial Vehicles (UAV) and Aerial Common Sensor at Fort Huachuca, Arizona, he helped field the Army's first UAV.

Colonel Knarr retired from the Army in February 2002. In addition to the National War College, his civilian education includes a doctorate in education. He was a Senior Army Aviator and parachutist. His awards included two Legions of Merit and the Republic of Vietnam Gallantry Cross unit citation.

After retiring from active duty, Bill worked with the Institute for Defense Analyses as a senior project leader and then from 2011-2021 he worked with the Joint Special Operations University in Tampa, Florida, as a senior fellow, first resident and later non-resident/part-time. During that time, he deployed several times to Iraq and Afghanistan and wrote a number of books and studies on those deployments.