A party official and well-known technocrat, Černík was a strong supporter of the Prague Spring reforms of 1968.

After party leader Alexander Dubček was replaced with Gustáv Husák in 1969, Černík publicly distanced himself from his previous support of reform.

He attempted a political comeback in the early 1990s after the end of the communist regime.

In 1994, he survived a serious car accident; shortly afterward he died in Prague of cardiac arrest.

His grave portrait at the Vyšehrad Cemetery was created by Jitka Malovaná.