 Marcinkowski was born in Hamtramck, Michigan of Polish descent.After finishing high school in 1973, Marcinkowski, then 18, clerked in the Computer Systems Division of the Federal Bureau of Investigation.In 1975, he enlisted in the United States Navy, where, as an Operations Specialist he became an expert in anti-submarine warfare, was an 
Air Controller, and collected shipboard intelligence on the Soviet Navy during the Cold War.