He was born Henriks Štubis in Kreis Hasenpoth in the Courland Governorate of the Russian Empire (present-day Latvia) in a family of Latvian ethnicity.

The police officers deemed responsible for this security lapse were sacked, and Zakovsky was transferred in January 1935 as head of the Leningrad NKVD, replacing Filipp Medved.

It was impossible to move in the milling throng, but this time people were sitting not on bundles, but on quite respectable-looking trunks and suitcases still covered with old foreign travel labels.

During a plenum of the Central Committee on 3 March 1937, he delivered a long personal attack on his former boss Genrikh Yagoda, whom he accused of impeding the investigations in Leningrad and generally refusing to take action against former oppositionists in the communist party.

"[4] Zakovsky was planning a major trial of leading Leningrad communists, including Zhdanov's deputy, Mikhail Chudov (who was executed in 1937), his wife Lyudmila Shaposhnikova, Boris Pozern (shot in 1938), and others.

This case was included in the famous Secret Speech which the Soviet leader Nikita Khrushchev delivered to the 20th Communist Party congress, in 1956, denouncing crimes committed under Josif Stalin.

You will have to study it carefully, and remember well all questions the Court might ask and their answers...If you manage to endure it, you will save your head and we will feed and clothe you at the Government’s cost until your death.

In spring 1938, Zakovsky became a victim of the Great Purge, as Order 49990, calling for the mass arrests of ethnic Latvians, was applied to serving NKVD officers.