Born in Focșani, Voinov was educated in his native country, following which he entered the magistracy.
He first served as a prosecutor and then, from 1862 to 1864, presided over the Putna County tribunal.
Voinov was eventually attracted by politics, serving a number of terms as deputy and senator.
From November 1883 to January 1885, he was Justice Minister in the National Liberal government of Ion C. Brătianu.
He later joined the United Opposition and then the Constitutional Party of Petre P.