Gershuni was born in Kaunas, in the Kovno Governorate of the Russian Empire (present-day Lithuania), to a petty bourgeois family of Lithuanian Jews.

[2] After his release he joined with fellow revolutionaries including Catherine Breshkovsky, Victor Chernov, Alexander Kerensky and Yevno Azef to establish the Socialist-Revolutionary Party in 1901.

Gershuni also founded the SR Combat Organization in 1902, which planned and executed the assassination of Dmitry Sipyagin, the Minister of Interior, in April 1902 and of N. M. Bogdanovich, the Governor of Ufa, in May 1903.

In February 1904, Gershuni was tried by a military court in Saint Petersburg and received a death sentence, which later was reduced to life imprisonment at a hard labour camp by Tsar Nicholas II of Russia.

[5] From China he traveled to Japan and the United States, giving speeches from San Francisco to New York City in support of the socialist-revolutionary causes.