Roja was born on 4 April 1876 in the village of Bryńce Zagórne near Żydaczów, AustrianGalicia to a family of forester Józef Roja and Maria née Trzcińska. He graduated from the Austro-Hungarian ArmyCadet School in Vienna. In 1899 he was promoted to Second Lieutenant, and served with the 36th Land Defence Regiment in Kolomyja. In 1905, due to poor health, he was transferred to army reserve. Roja cooperated with Austro-Hungarian intelligence. For a time, he studied law and medicine at Jagiellonian University, and work as a civil servant in Kraków. After the outbreak of World War I, Roja joined Polish Legions. He was a close coworker of Józef Piłsudski, but after Oath crisis left the Legions and rejoined Austro-Hungarian Army. In early 1918 he served in Graz, returning to Kraków after several months. Bolesław Roja immediately got involved in Polish patriotic activities. In late October 1918 he took over former Austrian Military Command in Kraków, and, on 1 November, the Regency Council, in recognition of his outstanding services, promoted him to the rank of Generał brygady and named him commandant of Kraków garrison. Roja's promotion was soon confirmed by Polish Commander-in-chief, Jozef Pilsudski.
Between February and August 1919, Roja commanded the Polish 2nd Legions Infantry Division, fighting for the return of Poland's sovereignty against the Red Army in present-day Belarus. On 8 August 1919, his unit captured Minsk, after which Roja was transferred to the command of the garrison of Kielce. In March 1920 he commanded Polish Army in Pomerelia,Dariusz Krakowiak, Józef Piłsudski i jego czasy.. and in August 1920, he was commandant of Narew Operational Group of the Polish Northern Front. Roja was skeptical about Polish victory in the war against Soviet Russia. In July 1920, when the Red Army reached the suburbs of Warsaw, he planned to declare independence of Pomerelia, and sign a separatist peace with the Soviets. Due to his defeatist approach and involvement in politics, he was in late August 1920 demoted from his position. On 20 September, Roja was transferred to reserve until 1922. In the late 1920s, Roja frequently criticized Józef Piłsudski and his sanacja government. In 1928 he was elected to the Sejm as member of Stronnictwo Chłopskie peasant party. He was chief deputy of Military Commission of the Parliament, and in December 1929 he resigned from the Sejm. In August 1930, Roja wrote an open letter to Pilsudski, but the document was confiscated by the censorship before its official release. In 1937, upon an order of General Tadeusz Kasprzycki, Roja was interned at a psychiatric ward of the Kraków's military hospital. Roja did not fight in the Invasion of Poland. In late 1939, he became involved in charity activities of the Polish Red Cross. In March 1940, Roja was arrested by the Germans and placed in the infamous Pawiak prison in Warsaw. In May 1940 he was transferred to Sachsenhausen concentration camp, where he was murdered on 27 May 1940.