At the age of 17, he joined the Wallachian Army, and, in 1840, took part, alongside Eftimie Murgu and Cezar Bolliac, in Mitică Filipescu's conspiracy against Prince Alexandru II Ghica.

One of his contributions to the magazine singles him out as a radical liberal: Despre starea socială a muncitorilor plugari în Principatele Române în deosebite timpuri ("On the Social Status of the Ploughmen of the Romanian Principalities at Various Times") argues for a land reform, aimed at dispossessing the boyars of large plots of land (that would in turn be awarded to landless peasants); it was used as reference by Karl Marx in his succinct analysis of the events, a fact which was to earn Bălcescu credentials in Communist Romania.

In early 1849, Bălcescu was in Istanbul when the Hungarian revolutionary armies under Józef Bem mounted a successful offensive against Habsburg forces and their Transylvanian Romanian allies.

Marxist-inspired historiography has celebrated this as an agreement; in fact, Bălcescu's papers reveal that he viewed the peace offering as unsatisfactory for Romanians, and that Avram Iancu rejected it altogether (while agreeing to a temporary armistice).

When this latter conflict drew to a close, the Romanians in Transylvania, although never particularly welcoming of the Russian presence, surrendered their weapons to the reinstated Habsburgs (Iancu's loyalty to the dynasty had been the subject of a parallel dispute between him and the Wallachians).

Bălcescu's most important work is Românii supt Mihai-Voievod Viteazul ("Romanians under the Rule of Michael the Brave"), which he wrote in exile in 1849 – first published posthumously by Alexandru Odobescu in 1860.