Samuel was born on the 4th of August, 1926, in Madison, New Jersey. He was involved with sports in high school and he graduated from the Newark Academy in 1945 before attending the US Military Academy. Samuel graduated with the class of 1949 and got married to the daughter of the commander of the Navy Ammunition Depot in Lake Denmark, New Jersey.

Commissioned as a Second Lieutenant in the Army, Samuel attended the Officer's Basic Course at Fort Riley, Kansas in August of 1950 and then attended the Infantry Officer's Basic and Basic Airborne courses at Fort Benning, Georgia. After being promoted t First Lieutenant, he commanded a platoon of Company C, 5th Cavalry Regiment, 1st Cavalry Division, which was stationed in Japan after World War 2 but transferred to Korea just weeks after the beginning of the Korean War. After being in country for three months, it was Samuel's actions during the UN Offensive that would cost him his life and earn him the Medal of Honor. The citation reads:

1st Lt. Coursen distinguished himself by conspicuous gallantry and intrepidity above and beyond the call of duty in action. While Company C was attacking Hill 174 under heavy enemy small-arms fire, his platoon received enemy fire from close range. The platoon returned the fire and continued to advance. During this phase, one of his men moved into a well-camouflaged emplacement, which was thought to be unoccupied, and was wounded by the enemy who were hidden within the emplacement. Seeing the soldier in difficulty he rushed to the man's aid and, without regard for his personal safety, engaged the enemy in hand-to-hand combat in an effort to protect his wounded comrade until he himself was killed. When his body was recovered after the battle 7 enemy dead were found in the emplacement. As the result of 1st Lt. Coursen's violent struggle several of the enemies' heads had been crushed with his rifle. His aggressive and intrepid actions saved the life of the wounded man, eliminated the main position of the enemy roadblock, and greatly inspired the men in his command. 1st Lt. Coursen's extraordinary heroism and intrepidity reflect the highest credit on himself and are in keeping with the honored traditions of the military service.

When Samuel died on the 12th of October, 1950 at the age of 24 years old, he was one of thirty West Point class mates that died in the Korean War and many were platoon commanders. Nine months later, his Medal of Honor was presented to his fourteen month old son, Samuel Jr, by the Joint Chiefs of Staff Chairman and General of the Army, Omar Bradley in a ceremony at the Pentagon. Three months later, in September of 1951, the Newark Academy renamed their athletic ground the Coursen Memorial Field in his honor and in 1956, the US Army christened a 172 foot passenger and vehicle ferry in his honor. The Lt Samuel S Coursen still operates today, taking passengers from Manhattan to Governor's Island. Samuel Streit Coursen is buried in the United States Military Academy Post Cemetery in West Point, New York: Section VII, Row E, Grave 230.