In September 1917, he commenced his undergraduate studies at the University of Kazan, but the events following the October Revolution forced him to go back to Dagestan in early 1918.
[2] After the British occupation of Dagestani ports during the Dagestan Campaign, Mammadbeyov was delegated to Astrakhan to work with local Muslim labourers.
[2] After the establishment of the Soviet power in the North Caucasus, Mammadbeyov was appointed head of the Dagestani branch of the Cheka, as well as People's Commissar of Internal Affairs of Dagestan.
[4] While serving in that position, Mammadbeyov effectively suppressed anti-Soviet movements in Chechnya and Dagestan and trained native Dagestanis in civil service, which experienced severe shortage in local cadres.
[3] On 27 September 1937, in the midst of the Great Purge, Mammadbeyov was removed from his position, expelled from the Communist Party and arrested as an "enemy of state" based on false allegations, accused of being an accomplice to "bourgeois nationalists".