He was born in Constantinople in 1873, to the Jewish middle classes. He was a close friend of Lenin, and was initially a member of the Social Democratic Labour Party. Following a disagreement between Lenin and Martov, the SDlP split. Those who believed in a minority rule became the Bolsheviks, those who believed in a large number of activists became the Mensheviks.
After the victory of the Bolsheviks, Martov was forced into exile, as was common Communist policy at the time. He died in 1920.