Upon graduating from Seton Hall University in May 1969, Dennis was commissioned a 2nd Lieutant in the Army – Infantry. He finished the Infantry Officers basic Course at Ft. Benning, Georgia and was assigned to 1st Army as a Training Officer in a Basic Training Company at Ft. Dix, New Jersey. In June 1970, Dennis was assigned to the 7th Infantry Division at Camp Casey, Republic of Korea. So the existing Company Commander of D Company, 7th Medical Battalion (who played college football at Northwestern) could play on the 7th Division football team, Dennis was assigned to take his place as the Company Commander. Around year-end 1970, the 7th Infantry Division and the 2nd Infantry Division merged with the 2nd Infantry Division succeeding the 7th and the 7th’s colors returning to the States. Dennis then became the Company Commander of C Company, 2nd Medical Battallion at Camp Stanley. In June 1970, Dennis returned to the States and was released from active duty.