Robert Reem was born on October 20, 1925, in Lancaster, Pennsylvania. He served as a page in the Pennsylvania House of Representatives during his senior year of high school from January to May 1943, and he enlisted in the U.S. Marine Corps on June 17, 1943. Pvt Reem went on active duty beginning August 21, 1943, completed basic training at Parris Island, South Carolina, in October 1943, and was then selected for an appointment to the U.S. Naval Academy. He attended the Naval Academy Preparatory School at NTC Bainbridge, Maryland, from October 1943 until he entered the U.S. Naval Academy on June 21, 1944; receiving his commission as a 2ndLt in the U.S. Marine Corps on June 4, 1948. Lt Reem next attended the Basic School and Infantry Officer Course at MCB Quantico, Virginia, from June 1948 to June 1949, and then remained with the Special Training Regiment at MCB Quantico until August 1949. His first assignment was with 3d Battalion, 6th Marine Regiment of the 2d Marine Division at Camp Lejeune, North Carolina, from August to December 1949, and then with his unit assigned the Sixth Fleet in the Mediterranean from December 1949 to August 1950. His final assignment was as a Platoon Commander in Company H, 3d Battalion, 7th Marine Regiment of the 1st Marine Division in South Korea, where he participated in the Inchon Landing, the capture of Seoul, and the fighting into North Korea before he was killed in action on November 6, 1950. On February 8, 1952, Lt Reem was posthumously awarded the Medal of Honor for his heroic actions at the time of his death. He was originally buried in the United Nations Cemetery near Hamhung, North Korea, but was later returned to the United States, where he was buried at Arlington National Cemetery.

His Medal of Honor Citation reads:

For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty as a Platoon Commander in Company H, Third Battalion, Seventh Marines, First Marine Division (Reinforced), in action against enemy aggressor forces in the vicinity of Chinhung-ni, Korea, on 6 November 1950. Grimly determined to dislodge a group of heavy enemy infantry units occupying well-concealed and strongly fortified positions on commanding ground overlooking unprotected terrain, Second Lieutenant Reem moved slowly forward up the side of the ridge with his platoon in the face of a veritable hail of shattering hostile machine-gun, grenade and rifle fire. Three times repulsed by a resolute enemy force in achieving his objective, and pinned down by the continuing fury of hostile fire, he rallied and regrouped the heroic men in his depleted and disorganized platoon in preparation for a fourth attack. Issuing last-minute orders to his non-commissioned officers when an enemy grenade landed in a depression of the rocky ground in which the group was standing, Second Lieutenant Reem unhesitatingly chose to sacrifice himself and, springing upon the deadly missile, absorbed the full impact of the explosion in his own body, thus protecting others from serious injury and possible death. Stout-hearted and indomitable, he readily yielded his own chance of survival that his subordinate leaders might live to carry on the fight against a fanatic enemy. His superb courage, cool decisiveness and valiant spirit of self-sacrifice in the face of certain death reflect the highest credit upon Second Lieutenant Reem and the United States Naval Service. He gallantly gave his life for his country.