Leonard Matthew Apostolu (1918-1985) was born in New York City to Daniel Apostolu (1882-1954) and Rose Mary Terrizzi (1891-1991). Apostolu attended Dewitt Clinton High School in the Bronx, New York, and continued his education at the New York School of Photography from 1937 to 1938, and New York University Night Extension School from 1938 to 1939. While attending school, Apostolu worked for Kingsdale Photographic Studio in 1936; for Allied News Pictures Inc. in 1937; for Adam's Studio from 1937 to 1938; for Universal Camera Corporation from 1938 to 1939; and at Photographic Specialist Co. from 1939 to 1940.

In 1941 Apostolu enlisted in the United States Army. He served in the 161st Signal Photographic Company where he worked as a Technical Sergeant through 1943 and then was moved to the 163rd Signal Photographic Company in Fort Sam Houston, Texas, until 1944. From 1944 to 1945 Apostolu worked as the Chief of Photographic Laboratory for the US Army Signal Office Headquarters Fourth Service Command in Atlanta, Georgia. He was honorably discharged in 1945 and received the Army Commendation Ribbon. Apostolu stayed in Atlanta and married Alice McGeorge (1916-1997) in 1942 and they had two daughters, Dawn Apostolu (1946- ) and Lynn Rose Apostolu (1952- ). After being discharged from the Army, Apostolu worked as a photographer for Rich's and Davison's, and as a lithographer for National Graphics Inc., before retiring in 1984.