He returned to Poland and joined the Polish military. He commanded units near Kamieniec, Podolski and elsewhere. During the Soviet-Polish war of 1920, he commanded the unit Strzelcy Kaniowscy. Bołtuć, still a captain, commanded the defence of Zamość. Then he took Wyszków, the location of the puppet government organiced by the Bolsheviks.
During the interwar period, he worked for the General Command and later held command functions in Wilno and Toruń. His nomination to the rank of general was held back for several years, in part because of his anti-religious attitude and his reservations about Poland's military spending patterns. He was known for clarity of judgment and leadership skills.[citation needed]
During World War II, he commanded an Operation Group, a unit short of an army, within the Army Pomorze, the only Polish unit that entered German territory (in East Prussia) for two days during the September Campaign and withstood attacks of much larger German forces. The danger of being flanked forced Boltuc to withdraw to Modlin. When the Modlin Fortress could accept only his officers but not his soldiers, he let his soldiers be demobilised, but most refused to leave. He also encouraged volunteers to go with him to try to sneak through the German Siege of Warsaw. According to written family records, he said while he was leaving home before the war, "This is not the war we are going to win and I am not the kind of a soldier who would surrender".
On the morning of 22 September, he was killed at the Battle of Łomianki from sniper fire while he was leading the charge.
Most of his soldiers were buried at the Łomianki cemetery, near Warsaw. Boltuc's tomb, in a form of a field stone, is at the Powązki Military Cemetery, in Warsaw.
^Bielski, Mieczysław (13 December 2017). "Bołtuć Mikołaj" (in Polish). Retrieved 19 April 2018.
^There are numerous places called Rzeczyca – in several countries; see the disambiguation page in Polish Wikipedia, pl:Rzeczyca, for a more extensive list. It is unclear which one was the seat of the Łabuński family. One source says that the family was based in Polish Inflanty.[1] That article in Polish Wikipedia associates Polish Livonia with Latgale, a historical and cultural region of Latvia which includes Rēzekne (Polish: Rzeżyca); yet another possibility.
^(in Polish) Dziennik Personalny Ministra Spraw Wojskowych nr 1 z 02.01.1928
^(in Polish) Zbigniew Mierzwiński: Generałowie II Rzeczypospolitej. Warszawa: Polonia, 1990, s. 45
^(in Polish) M.P. z 1929 r. nr 274, poz. 630 „za zasługi na polu organizacji i wyszkolenia wojska”.
^(in Polish) Dziennik Personalny Ministra Spraw Wojskowych nr 20 z 15 lipca 1922
^(in Polish) M.P. z 1937 r. nr 64, poz. 96 „za zasługi w służbie wojskowej”.
^(in Polish) M.P. z 1938 r. nr 258, poz. 595 „za zasługi w służbie wojskowej”.
Monograph: Generał Mikołaj Bołtuć Wizerunek Żołnierza author: Bohdan Królikowski Nakładem Stawarzyszenia Katolików Wojskowych ISBN83-906281-1-2, Warszawa/Warsaw 1998.