Mary Cugini Necko was born 14 November 1924, in Brighton, Massachusetts. She graduated from high school in 1942 and went to work as a statistical clerk for the U.S. Department of Commerce, while also studying accounting at Boston University.
In November 1944, Necko joined the Women Marines. She was sent basic training at Camp Lejeune, North Carolina, in January 1945, and then went to work in reimbursement at Marine Corps Headquarters in Arlington, Virginia. In May 1946, Necko was discharged as a corporal.
Necko attended Strayer Business College after her discharge and then worked for a finance company in Washington, DC. In 1948, she married Val Necko and they had two children. Necko also worked for the Navy Department as a civilian and at the Federal Building as a meteorological technician. She has volunteered at a Veterans Administration hospital and is involved with the Women Marines Association.