He studied mathematics at the University of Bucharest, and then started his research as a member of Simion Stoilow's seminar on complex functions.
[3] In 1957, Ganea published in the Annals of Mathematics a short, yet influential paper with Samuel Eilenberg, in which the Eilenberg–Ganea theorem was proved and the celebrated Eilenberg–Ganea conjecture was formulated.
[4] Later that year at an international conference on geometry and topology in Iași, the two met Peter Hilton, starting long mathematical collaborations.
Ganea left for France in 1961, where he obtained in 1962 his Ph.D. from the University of Paris under Henri Cartan,[3] with thesis Sur quelques invariants numeriques du type d'homotopie.
[2] In 1962, he gave an invited talk at the International Congress of Mathematicians in Stockholm, titled On some numerical homotopy invariants.