Caldarelli received his Doctor of Philosophy from SISSA, after which he was a postdoc in the Department of Physics and School of Biology, University of Manchester.
He then worked at the Theory of Condensed Matter Group, University of Cambridge, where he worked with Robin Ball and stayed in Wolfson College. He returned to Italy as a lecturer at National Institute for Condensed Matter (Istituto Nazionale per la Fisica della Materia) and later as Primo Ricercatore in the Institute of Complex Systems of the National Council of Italy. In this period he was also the coordinator of the Networks subproject, part of the Complexity Project, for the Fermi Centre.
He also spent some terms at University of Fribourg (Switzerland) and in 2006 he has been visiting professor at École Normale Supérieure in Paris.
The activity of Caldarelli is mainly focused on scale-free networks, complex networks and systems biology. He has been coordinator of the European project COSIN, one of the first international activities based on the study of complex networks.
He is presently coordinator of the European project FOC on the study of financial networks and the project MULTIPLEX on Multi-level Complex Networks. He has published numerous papers in physics and interdisciplinary journals, including Physical Review Letters and Nature.
His work on beauty and the stable marriage problem has been reported in the press
Lieutenant Artillery of Italian Army, 1993-1994.
Married Raffaella Frondoni, September 18, 1997.