In his youth Mankell was a left-wing political activist and participated in the Protests of 1968 in Sweden, protesting against, among other things, the Vietnam War, the Portuguese Colonial War, and the apartheid regime in South Africa. Furthermore, he got involved with "Folket i Bild/Kulturfront" which focused on cultural policy studies. In the 1970s, Mankell moved from Sweden to Norway and lived with a Norwegian woman who was a member of the Maoist Workers' Communist Party. He took an active part in their activities but did not join the party.