After he finished his high school studies in Romania, he went to Prussia in 1847 to study in the German military academies and in 1853, with the approval of the Romanian government, he joined the Prussian Army as a sub-lieutenant.

From 1869 to 1870, Manu, a colonel, was part of the cabinets of Dimitrie Ghica and Manolache Costache Epureanu, heading the War Ministry.

During his tenure, he initiated the creation of a modern water supply network for the city; the works were interrupted between 1877 and 1878, but by 1879 over ten kilometers of pipes were installed.

[2] As the Romanian War of Independence began in 1877, General Manu was the commander of the 4th division, in charge of defending Romania in Oltenița, Corabia, Bechet, Islaz and Turnu Măgurele, but following the offensive, his division took part in the campaign on the plains of Bulgaria, in Pleven and Vidin.

On 27 November 1891, in the Lascăr Catargiu cabinet, he became the Minister of State Property, but quit to become the President of the Chamber of Deputies, a post he held until 1895, when he retired.