From this position Grósz supervised most of the state-controlled media. During the 1970s he also served as first secretary of the party committee in two Hungarian counties. During 1984–1987, he was the first secretary of Budapest's party committee. On 25 June 1987 he was appointed prime minister. Grósz presented a frank appraisal of the deteriorating Hungarian economic situation before parliament, the first time in the communist state that any government official had publicly detailed such problems.
At a party convention on 22 May 1988, Grósz seized the reins of the party from János Kádár, who had been its leader for thirty-two years, and thus became general secretary of the Communist Party. Grósz then announced an austerity program. As demands for reform in Hungary mounted, he agreed to dissidents' demands that the archives be opened on the secret trial of Imre Nagy. Eventually Grósz, who allied himself with Soviet leader Mikhail Gorbachev, gave way to a growing demand for change. He authorized election reform, including a multiparty system. Hungary was the only one of the former Soviet bloc countries where the reformist revolution came from above. Grósz remained prime minister until November 1988 and leader of the party until October 1989. He died on 7 January 1996 in Gödöllö, Hungary.
Grósz, Károly. Nemzeti összefogással a reformok sikeréért [National Union for the Success of Reforms]. Budapest: Kossuth, 1989.; Grósz, Károly. Szocializmus és korszeráség: Nemzeti és történelmi felelősség [Socialism and Modernization: National and Historical Responsibility]. Budapest: Kossuth, 1987.; Saxonberg, Steven. The Fall: A Comparative Study of the End of Communism in Czechoslovakia, East Germany, Hungary, and Poland. Amsterdam: Harwood Academic, 2001.