Born in Giurgiu, the son of a teacher,[1] he attended the Matei Basarab High School in Bucharest.

After completing his undergraduate studies at the Faculty of Mathematics of the University of Bucharest in 1924, he went to Paris, where he enrolled at the École Normale Supérieure and the Sorbonne.

"[4] Nicolescu was awarded the Legion of Honour, Commander rank,[2] and was elected in 1972 member of the German National Academy of Sciences Leopoldina.

[5][6] At the International Congress of Mathematicians held in Vancouver, British Columbia, Canada in 1974, he was elected vice-president of the International Mathematical Union, a position he held from 1975 until his death (his term was completed by Gheorghe Vrănceanu).

[7] A technical high school in Sector 4 of Bucharest bears his name, and so does a boulevard in Giurgiu.