Though small in stature, Mario Gregorio was a stalwart, defensive-minded guard in three seasons at Georgetown from 1935 to 1938.

A first generation American whose parents settled in Washington from their native Sicily, Gregorio earned a scholarship from his athletic play at Washington's Central HS. Gregorio wasn't counted upon to score, and usually didn't, for the most part. A pair of seven point finishes versus Yale and Carnegie Tech made up the majority of his three year scoring totals.

Following graduation from the School of Foreign Service in 1940 and service in the U.S Army Air Corps in World War II, Gregorio joined the Federal Bureau of Investigation, serving overseas for seven years as the legal attache at the American Embassy in Rome. Following retirement from the Bureau in 1967, he worked twenty years as a private legal and security consultant, and enjoyed an extended retirement until his death in 2014 at the age of 91.