Born in Caracal, his parents were Vasile Măinescu, a clerk at Poșta Română, and his wife Theonia (née Dobritescu).
He studied for a year at the medical faculty of the University of Bucharest, followed by another at the Dramatic Arts Conservatory under Constantin I. Nottara.
Măinescu then entered the law faculty at Bucharest, transferring to the University of Iași and earning his degree there in 1923.
His first book, the 1929 poetry volume O picătură de parfum..., drew favorable reviews from Alexandru A. Philippide, Tudor Arghezi and Demostene Botez.
His work appeared in Gazeta literară, Steaua, Iașul literar, Orizont, Tribuna, Albina, Tânărul scriitor, Familia, Presa noastră, Cravata roșie, Luminița, Arici Pogonici, and Urzica.