Paul Dean Foster was born on 4 February 1941 in Cherokee County, Oklahoma. After graduating from Roseville High School in Roseville, Michigan, he enlisted in the U.S. Army in 1959. His initial training focused on Combat Engineering, followed by additional training as a Radio Operator and in two foreign languages. Foster qualified as a Jumpmaster Parachutist in both Static Line and Military Free Fall (HALO), completing more than 1,000 parachute jumps. He served two combat tours in Vietnam with the 5th Special Forces Group (Airborne). During his first tour, he was assigned to Detachment B-57, Gamma Project, which was involved in covert intelligence collection. Foster and Major Curtis Terry lived among the Montagnard people in Ban Don village, Central Highlands, Vietnam. Their unclassified role was as United States Agency for International Development (USAID) representatives, providing supplies and repairing infrastructure. Their classified mission included reconnaissance patrols along the Cambodia/Vietnam border.

As a Spanish-speaking Team Sergeant with the 8th SF Group, Foster led a four-man team to Honduras in 1969 during the Honduran-El Salvadoran "Soccer War." With limited international communications available, the team constructed and operated a communication center that facilitated coordination between the respective ambassadors and Washington, D.C. Foster's proficiency in German led to his assignment to Detachment A, Berlin Brigade in 1979. The detachment’s missions included "Stay Behind" operations in the event of an invasion of Berlin and antiterrorism responsibilities in Europe. As the Signal NCO, he designed and supervised the construction of a Mobile Communications Center and developed high-gain Yagi and log-periodic antennas for operational use.

During his more than 26 years in the Army, including 20 years with Special Forces, Foster received awards such as the Bronze Star Medal, Meritorious Service Medal, and the Army Commendation Medal with OLC Large, among others. After retiring from the military in 1986, he earned a Bachelor of Science in Education and later retired from teaching in 2006. Foster has participated in community activities, serving on the Faulkner County Election Commission, leading the Faulkner County Republican Committee, and co-founding the Arkansas Military Veterans Hall of Fame.