Jules Barry Kroll was born in 1941 in Brooklyn, New York. His father owned a printing company and his mother was a homemaker. Young Jules did well in school, attended Cornell University where he earned a bachelor's degree in 1963, then went on to Georgetown University Law School. He received his law degree from Georgetown in 1966, took the New York bar exam, and worked as an assistant district attorney in Manhattan. Kroll's experiences in the D.A.'s office included prosecuting a wide range of crimes and working with up and coming politicians including Robert F. Kennedy. After a few years, however, Jules branched out on his own and founded Kroll Associates in 1972.