Vukmirović was born on 1 August 1912 in the Bulgarian town of Bratsigovo. His father , originally from the Montenegrin town of Rijeka Crnojevića, took part in the Ilinden Uprising in 1903. After the uprising was suppressed, Nikola was imprisoned in the Ottoman Empire later moving to Bulgaria where he married Stojanka with whom he had three sons: Boro, Andro and Rade. In 1914, the family moved to Peć where Boro completed elementary school and six grades of gymnasium. At that time, the Peć gymnasium had only six grades and further education had to be completed in Prizren for which his parents didn't have the funds. After completing the sixth grade, he found a job as a labour worker. He worked in Peć and other places in Kosovo.