He was born in Bucharest, Romania, and finished high school at the Nicolae Bălcescu High School (now Saint Sava National College). He did his undergraduate studies in the Physics Department of the University of Bucharest, graduating in 1995. His last year there he studied at the Niels Bohr Institute (NBI), Copenhagen University, with a scholarship which continued into the following year. In 1996 he joined the Physics Department of the State University of New York at Stony Brook from which he received his PhD in May 2000, with thesis written under the direction of Peter van Nieuwenhuizen. From 2000 to 2002 he was a postdoc at the Institute for Advanced Study in Princeton, after which he was an assistant research professor at Brown University until 2006. From 2007 to 2009 he was an assistant professor at the Global Edge Institute of the Tokyo Institute of Technology in Japan. Since 2010, Năstase holds a permanent position as assistant professor at IFT-UNESP in Brazil.