Iliopoulos graduated from National Technical University of Athens (NTUA) in 1962 as an Mechanical-Electrical Engineer. He continued his studies in the field of Theoretical Physics in Paris University, and in 1963 he obtained the D.E.A, in 1965 the Doctorat 3e Cycle, and in 1968 the Doctorat d' Etat titles. Between the years 1966 and 1968 he was a scholar at CERN, Geneva. From 1969 till 1971 he was a Research Assosiate in Harvard University. In 1971 he returned in Paris and began working at CNRS. He also held the director position of the Laboratory of Theoretical Physics of Ecole Normale Superieure between the years 1991-1995 and 1998-2002. In 2002, Iliopoulos was the first recipient of the Aristeio prize, which has been instituted to recognize Greeks who have made significant contributions towards furthering their chosen fields of science. Iliopoulos and Maiani were jointly awarded the 1987 Sakurai Prize for theoretical particle physics. In 2007 Iliopoulos and Maiani received the Dirac Medal of the ICTP "(f)or their work on the physics of the charm quark, a major contribution to the birth of the Standard Model, the modern theory of Elementary Particles."