Having secretly joined Musavat party in 1911, Hajinski started his open political activities after Russia's February Revolution of 1917. He also actively participated in establishment and operations of the "Hummet" newspaper. On March 22, 1917 Interim Executive Committee of Muslim Council was established and Hajinski was appointed its chairman. He participated in the Baku summit of Caucasian Muslims and later in Moscow summit of Russian Muslims in May of the same year. He was subsequently elected a deputy to the Russian parliament from Azerbaijan. On November 15, 1917, he was appointed deputy Commissar of Industry and Trade (Mammad Yusif Jafarov) of Transcaucasian Commissariat and from April 22, 1918, he served as the Minister of Industry and Trade of Transcaucasian Democratic Federative Republic.