He has been working since 2001 at CERN, on leave from the University of Milan, where he directed the Magnets & Superconductors for the LHC project, worth €1.7 billion, half of the machine's entire budget.

He was an academic researcher for many years after, interested in applied superconductivity for particle accelerators and in 1992 he became Professor of Experimental Physics in the University of Milan.

During the 1990s, Rossi was involved in many experiments such as the Superconducting Cyclotron (SC) currently in Catania, HERA at DESY in Hamburg and Large Hadron Collider at CERN.

[7][8] In 2011 at the international symposium on subnuclear physics held in Vatican City, he gave a talk The Large Hadron Collider of CERN and the Roadmap Toward Higher Performance.

[9] Since 1985 Rossi is one of the founders of "Euresis", a Milan-based association for the promotion of scientific culture established in Milan.