Lenart was a member of the federal parliament (whose name changed several times) from 1960 to 1990, and was Speaker of the Slovak National Council from 1962 to 1963. He was also a member from 1971 to (?)1990. He served as Prime Minister of Czechoslovakia between 1963 and 1968.
Although ethnically Slovak, he became a Czech citizen after the countrysplit in 1993.
On the basis of insufficient evidence, on 23 September 2002 Lenárt was acquitted of treason charges (along with his co-defendant Miloš Jakeš), related to his handling (or lack thereof) of the Prague Spring events in 1968.[4] He was accused of attending a meeting at the Soviet embassy in Prague on the day after the 1968 Warsaw Pact invasion, planning to establish a new "workers and farmers'" government.
Jozef Lenárt was one of the most resilient figures in Czechoslovakia's communist hierarchy, occupying one post or another in the leadership for no less than a quarter of the century. That achievement was all the more remarkable because his career at the top straddled a succession of regimes and several abrupt changes in policy.
He died in Prague in 2004.
Major functions
1950–1953, 1957–1966, and 1970–(?)1990: Member of the KSS
1956–1958: Leading Secretary of the Regional Committee of the KSS
1958–1962: Secretary of the Central Committee of the KSS
1958–(?)1990: Member of the Central Committee of the KSČ