Born in Genoa, Italy, he received a degree from the University of Milan before moving to the US to pursue a career in Astrophysics research. He became an American citizen.
He was awarded the Nobel Prize in Physics in 2002 for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources. He has simultaneously held the position of professor of physics and astronomy (1982-1997) and research professor (since 1998) at Johns Hopkins University.