A trained doctor, Dubrovin gave up his practice to concentrate on opposing what he saw as creeping liberalism in the Russian aristocracy, turning his own movement, the Russkoe Sobranie, over to the newly formed URP in 1905 when he was appointed head of the new group's directorate. Both anti-Semitic and anti-Masonic he believed in the Zhidomasonstvo (Judeo-Masonic) conspiracy and took the lead in organising the pogroms of the Black Hundreds.
Gaining a popular following amongst the peasants, petite bourgeoisie and lumpenproletariat due to his demagogy, Dubrovin sat in the State Duma of the Russian Empire despite being a firm believer in absolutism and before organising a failed boycott of the Third Duma in 1907. Closely involved in the trial of Menahem Mendel Beilis, as later described in Bernard Malamud's novel The Fixer, Dubrovin himself fell foul of the law when his tendency towards violence saw him indicted for the murder of a fellow Duma member.
Within the URP Dubrovin was the leader of an extreme faction based around the Russkoe znamya newspaper and in 1910 this became the base of his support when the majority faction of the URP fell under Nikolai Markov. With Dubrovin somewhat lacking in charisma and seen as somewhat unbalanced, his faction fell into insignificance. He was shot and killed in 1918 for his activities against the October Revolution.