Jatindra Nath Mukherjee was named ‘Bagha Jatin’ after he killed a tiger single-handed and without any arms. He joined as a stenographer in the government of Bengal. He came in contact with Aurobindo Ghosh. While working for the Yugantar as a main leader, he met Naren (Manabendra nath Roy). Several sources mention Jatin as being among the founders of the Anushilan Samiti in 1900, and as a pioneer in creating its branches in the districts. In 1908 with many revolutionaries implicated in the Alipore Conspiracy Case, Jatin took the charge of Yugantar activities. Jatin was arrested in the Hawra-Shibpur Conspiracy Case, and those who were arrested with him were given the common name ‘Jatin’s gang’. They were so ruthlessly tortured that some of them died and some went insane. Jatin, though acquitted in this case also for want of evidence, was dismissed from service. When in jail, Jatin and Naren made a long term programme to capture power through armed insurrection. They planned to unite different groups of patriots and with this intention Naren travelled extensively all over India as a Sanyasi and organised the revolutionaries in Bengal and elsewhere. The leaders of various groups gathered together and chose Jatin Mukherjee and Rashbehari Bose as leaders for Bengal and northern India respectively.
Attempts were made to organise the Indian revolutionaries outside India also. A Yugantar Ashram was formed at San Francisco and the Shikh community took active part in the struggle for freedom. With the outbreak of the First World War, the Indian revolutionaries of Europe gathered together in Berlin to form the Indian Independence Party and sought German assistance, to which the German government agreed. Jatin was the Commander-in-Chief of the entire revolutionary forces. Naren, leaving Jatin in hiding in Baleswar (Orissa), went to Batavia to negotiate a deal with German authorities there for the shipment of arms and financial help.
Police, however, learnt about the plan. With occasional skirmishes, the revolutionaries, running through jungles and marshy land in torrential rain, finally took up position in an improvised trench in undergrowth on a hillock at Chashakhand in Balasore. On 9 September 1915, after heavy exchange of fire, police found Jatin seriously wounded. In many ways, Bagha Jatin represented the best of the militant nationalist tradition in this country.