The Department of Defense says Pruitt was killed Saturday by an improvised explosive device while conducting combat operations in Helmand province, Afghanistan.
Pruitt was assigned to First Marine Expeditionary Force Headquarters Group, Camp Pendleton, California.
Pruitt graduated from Pascagoula High School in 1992 and lived in Gautier when he enlisted in 1993.
Authorities say Pruitt was awarded the Purple Heart and other medals including the Marine Corps Good Conduct Medal and the Navy and Marine Corps Commendation Medal.
Scott Pruitt is survived by two daughters, ages 9 and 4, who live in California.