Born in Tecuci, his father Eni Șerban (later Șerbănescu) was a "paharnic" (cup-bearer) and a member of the minor "boyar" nobility; his mother was named Smaranda, and the couple had eighteen children. Theodor attended primary school in his native town, followed by high school at Academia Mihăileană in the capital Iași and then the military school in the same city. A distinguished student throughout, he entered the army as a second lieutenant of the military engineers. Having reached the rank of captain in 1869, he resigned. He re-entered the army in 1877, participating in the Romanian War of Independence as an officer with the general staff. He then worked at the War Ministry, rising to colonel and holding command posts in several garrisons (Bacău, Buzău, Brăila). He left the army for good in 1893 and mainly lived at his Vameș estate in Covurlui County. He served as prefect of Cahul County in 1876, but failed to make further inroads into political life. In 1868, Șerbănescu joined "Junimea", and in 1891 was elected a corresponding member of the Romanian Academy. He died in Brăila.