Maister was born in the Upper Carniolan commercial town of Kamnik, then part of Austria-Hungary. A career soldier, during World War I, he served in the Austro-Hungarian Army. In 1917, he was sent to Graz promoted to the rank of a major. In 1918, near the end of the war when it was obvious that Austria-Hungary was losing, the city council of Maribor proclaimed the annexation of Maribor to Austria. Maister organized Slovene volunteer forces of 4000 soldiers and 200 officers and in the night of 23 November 1918 seized control of the city of Maribor and the surrounding region of Lower Styria. This date has been recognized as a state holiday in Slovenia since 2005. The Slovene National Council for Lower Styria awarded him the rank of general on November 1. The German-speaking city was thus secured for the newly formed State of Slovenes, Croats and Serbs, which united with the Kingdom of Serbia into the Kingdom of Serbs, Croats and Slovenes on December 1.
On 27 January 1919, Austrian majority awaiting the American peace delegation at the city's marketplace were fired on by Slovenian troops under the command of Maister. Nine Austrians were killed and more than eighteen were seriously wounded. The responsibility for the shooting has not been conclusively established. Austrian sources accused Maister's troops of shooting without cause, while Slovenian witnesses, such as Maks Pohar, testified that the Austrians (some still in the uniforms of the pro-Austrian paramilitary organization called the Green Guard) attacked the Slovene soldiers guarding the city hall.[citation needed] The Austrian Germans allegedly attacked the police inspector, Ivan Senekovič, and then pressed towards the Slovenian soldiers in front of the city hall. A Slovenian version of this event involves an Austrian firing a revolver in the direction of the Slovenian soldiers, who responded spontaneously by firing into the civilian crowd.[citation needed] The event became known in German as the Marburger Blutsonntag (Marburg Bloody Sunday).
In November 1919, Maister's forces joined the Kingdom of SHS army's offensive in Carinthia. Maister joined them later and took part of the capture of Klagenfurt.[citation needed] After the Carinthian Plebiscite, in which majority of the local Slovenian population decided to remain part of Austria, Maister withdrew to private life. He spent most of his later life in an estate near Planina in Inner Carniola.
Maister also wrote poetry, which he published in two collected volumes, in 1904 and in 1929. Most of his poetry follows the Post-Romantic aesthetics, and is influenced by 19th century Slovene lyrical and patriotic poetry of Simon Jenko, Simon Gregorčič and Anton Aškerc.