He was a high school French teacher in Bacau and Bârlad, as well as a librarian.
He made his literary debut in 1891 in Lumea ilustrata; his first published volume, Nocturne, appeared in 1900.
He was a frequent contributor to the literary magazines of his day.
At Bârlad, from January to December 1900, he published the Samanatorist magazine Paloda literara.
He won the national prize for poetry in 1937.More than his verses, his contemporaries appreciated his discreet, modest and dignified personality.
He was a traditionalist poet, strongly influenced by Mihai Eminescu (as can be seen both in his debut volume and in the 1934 Poezii).
Nanu particularly focused on lyric poems characterized by religious and philosophical meditation.
Alone or in collaboration, he translated works by William Shakespeare, Pierre Corneille, Jean Racine, Guy de Maupassant, Paul Bourget and Alfred de Musset.