Educated at the artillery school, Putnik was commissioned in 1866. He graduated from the staff college in 1889 and became a general in 1903. Except for three periods when he was war minister (1904–05, 1906–08, 1912), he was chief of staff from 1903 to 1916. It was he who was mainly responsible for the skill, good equipment, and fighting spirit of the Serbian army.

Putnik headed a brigade in the two wars against Turkey (1876, 1877–78) and headed a divisional staff in the war against Bulgaria (1885). He was commander in chief in the two Balkan Wars (1912–13), routing the Turks at Kumanovo (October 1912) and—as field marshal—at Monastir, Tur. (now Bitola, Macedonia; November 1912). Largely because of him, the Bulgarians were defeated at Bregalnica (June–July 1913). When World War I began, Putnik, then in Austria, was escorted to Romania. In poor health, he resumed the post of commander in chief and routed overwhelming Austrian forces on Cer Mountain (August 1914), the first Allied victory in the war, and on the Kolubara River (November–December 1914). A year later, Putnik, carried in a sedan chair, shared in the retreat of his army across Albania. Relieved of his command, he retired to Nice.