He was a brilliant orator, tall, red-haired, yellow-eyed and pockmarked,[1] "robust, ruddy complexioned, vigorous, excitable, a heavy drinker, a gifted leader of men.

In 1906, he found a job as a lathe operator and joined the Petersburg Metalworkers' Union and the Russian Social Democratic Labour Party (RSDLP).

Here, for the first time, he was awarded a regular salary as a police informer, to supplement his wages as a metal turner, and was instructed by the Okhrana Director S. P. Beletsky to ensure that the different factions of the RSDLP never reunited.

As a secret agent, he helped send several important Bolsheviks (like Sergo Ordzhonikidze, Joseph Stalin, and Yakov Sverdlov) into Siberian exile.

He persuaded Lenin to appoint an Okhrana agent, Miron Chernomazov, as editor of Pravda as opposed to Stalin's candidate Stepan Shahumyan.

The tsarist regime was determined to keep the RSDLP split, meaning that conciliators and pro-party groups were targeted for sabotage, while liquidators and recallists were encouraged.

Stalin threatened Martov's sister and brother-in-law, Lydia and Fedor Dan by saying they would regret it if the Mensheviks denounced Malinovsky.

On 8 May 1914, he was forced to resign from the Duma after Russia's recently promoted Deputy Minister for the Interior, General Vladimir Dzhunkovsky, decided that having a police agent in such a prominent position might cause a scandal.

According to the British historian Simon Sebag Montefiore, his successful infiltration into the Bolsheviks helped fuel the paranoia of the Soviets (and, more specifically, Stalin) that eventually gave way to the Great Terror.