Who was the only Soviet leader who was also the chairman of the KGB?

Yuri Vladimirovich Andropov (15 June [O.S. 2 June] 1914 – 9 February 1984) was a Soviet politician and the fourth General Secretary of the Communist Party of the Soviet Union. Following the 18-year rule of the late Leonid Brezhnev, Andropov served in the post for only 15 months, from November 1982 until his own death in February 1984. Earlier in his career, Andropov served as the Soviet ambassador to Hungary from 1954 to 1957, during which time he was involved in the suppression of the 1956 Hungarian Uprising, and then Chairman of the KGB from 1967 until 1982.

Two days after Leonid Brezhnev's death, on 12 November 1982, Andropov was elected General Secretary of the CPSU, the first former head of the KGB to become General Secretary. His appointment was received in the West with apprehension, in view of his roles in the KGB and in Hungary. At the time his personal background was a mystery in the West, with major newspapers printing detailed profiles of him that were inconsistent and in several cases fabricated.