He studied musicology with André Pirro at the Sorbonne in Paris and in 1925 completed his doctoral dissertation on motets and chansons by Johannes Ockeghem, supervised by Guido Adler at the Universität Wien.

From the time of his stay in Paris, he had close contacts with Geneviève Thibault de Chambure (Comtesse de Chambure) and Nanie Bridgman [both well-known French musicologists from his generation], who also studied with Pirro.

Then in 1928 he began teaching musicology at the University of Zagreb as the private assistant professor.

In 1939 Plamenac went to the United States as the Yugoslav representative to the congress of the American Musicological Society in New York City, and decided to remain in New York due to frequent persecution of Jews in Europe and World War II, becoming an American citizen in 1946.

Plamenac was the first to indicate to the value of the works of Croatian renaissance and baroque periods, particularly compositions by Ivan Lukačić and Tomaso Cecchino) which he published in modern editions.