Russian Communist Party official who, while chief of the Soviet security police (NKVD) from 1936 to 1938, administered the most severe stage of the great purges, known as Yezhovshchina (or Ezhovshchina).

Nothing is known of his early life (he was nicknamed the “Dwarf” because he was but five feet tall and lame). Joining the Communist Party in March 1917, he was a political commissar in the Red Army during the Civil War and thereafter rose through several political posts, becoming a functionary for the Party Central Committee in Moscow by 1927 and one of Stalin's favourites. On April 29, 1933, he was named a member of a newly established central Purge Commission, which conducted a bloodless purge that ejected more than a million members from the Party. In January 1934, at the 17th Party Congress, he became a full member of the Central Committee and then, in February, succeeded L.M. Kaganovich in the key post of chairman of the Party Control Commission. In October 1937 he became a candidate member of the Politburo.

Meanwhile, on Sept. 26, 1936, he had succeeded G.G. Yagoda as chief of the NKVD and, in January 1937, acquired the newly created title of General Commissar of State Security. In these roles he perpetrated the grand excesses known as the Yezhovshchina, the cruel, ruthless elimination or repression of Stalin's enemies or alleged enemies in the Great Purge (see purge trials). The liquidations gradually extended from the Party leaders to the Party and state apparatchiki and finally to the general population.

By the summer of 1938, however, Yezhov himself had become the object of Stalin's suspicions, for reasons unknown. In December, L.P. Beria replaced him as head of the NKVD; and Yezhov, last heard of in January 1939, disappeared, probably executed.