From 1954 to 1958 he taught at the Higher School for Social Sciences at Central Committee of the Polish United Workers Party and from 1954 to 1956 at Dzerzhinsky Political-Military Academy in Warsaw.
He was also the cofounder and editor of the Newest History Quarterly (Dzieje Najnowsze)[1] and member of editorial staffs of Historical Quarterly (Kwartalnik Historyczny), Biographical Dictionary of Poland (Polski Słownik Biograficzny), Literary Monthly (Miesięcznik Literacki), Dictionary of Polish Learned Societies (Słownik polskich towarzystw naukowych), the Political Science Annual (Rocznik Nauk Politycznych).
Polish-American historian Anna Cienciala, in a review of this work, commented: "Of course, these [Madajczyk's] statements camouflage the realities of the PPR-Comintern relationship, but they may have been the price agreed with the censor for publishing the documents in the first place."
Cienciala further says that with the liberalization of Poland and the fall of communism, in 1989 Madajczyk wrote an extensive work on Soviet massacre of Polish POWs in Katyn.
[5] Hirschfeld noted that during the Cold War, Madajczyk was a vocal supporter of scholarly cooperation, breaching the Iron Curtain.