Mawhinney, born оn February 23, 1949, in
Lakeview, Oregon, Following enlistment, he attended
Scout Sniper School at
Camp Pendleton and graduated in April 1968. From there he received orders to
South Vietnam where upon arrival he was assigned as a rifleman to Lima Company
1st Battalion, 5th Marines,
1st Marine Division. He remained in this unit for three months until he was re-assigned to 5th Marine Regiment HQ Scout Sniper Platoon. There he worked as a scout sniper for different companies with the 1st, 2nd and 3rd Battalions. He also worked with the
South Korean Marines,
Force Recon, but the majority of his time was with Delta Company, 1/5 Marines. During this tour he is credited with 103 confirmed
North Vietnamese Army (NVA) and
Viet Cong (VC) kills and 216 probable kills. He spent 16 months in Vietnam, starting in early 1968. On
Valentine's Day 1969, Mawhinney encountered an enemy platoon and killed 16NVA soldiers with head shots. "It was the ultimate hunting trip: a man hunting another man who was hunting me", Mawhinney told the
Los Angeles Times. "Don't talk to me about hunting lions or elephants; they don't fight back with rifles and
scopes. I just loved it." Mawhinney sought to change the public perception about snipers, who he maintained save lives by sapping the enemy's will to fight. "My
rules of engagement were simple: If they had a weapon, they were going down. Except for an NVA paymaster I hit at 900yards, everyone I killed had a weapon", he said. After a chaplain declared him
combat fatigued, Mawhinney returned to the United States and served briefly as a rifle instructor at Camp Pendleton. == Civilian life and recognition ==