Born in St Louis, Missouri in 1930 to Sicilian immigrants Angelo and Marie Giammanco. In 1948 Giammanco robbed a Hollywood, California insurance office and served 15 months in prison. Giammanco was promoted to capo and continued to work in both California and St Louis. Giammanco also established strong ties with the Detroit Partnership. Giammanco eventually married Antonia Moceri and had five children.
He served as acting boss from 1975 to 1977.
On June 7, 1992 Giammanco died of natural causes in Detroit, Michigan. He is buried in Mt. Olivet Cemetery in Detroit.