He was born in Malovišta (Mulovishti), a village in the Ottoman Empire's Manastir Vilayet that today forms part of North Macedonia's Bitola Municipality.
He obtained a doctorate in 1922, with a dissertation about tradition and thought in Greek literature; one of the thesis committee members was Nicolae Iorga.
In 1929, it merged with Favonius, a magazine founded by Herescu, resulting in Revista clasică, with Papacostea numbering among the editors.
Filosofia, 1931; Sofiștii în antichitatea greacă, 1934, and Ștefan Zeletin, Viața și opera lui, 1935.
Together with Valaori and Gheorghe Popa-Lisseanu, he published editions of classical authors, including Livy, Virgil, and Xenophon; grammars of Latin and Greek; verse manuals and anthologies.