An adherent of Trotskyism, he is a member of the Central Committee of the Socialist Workers Party (SWP) and serves as its International Secretary.

He became involved in revolutionary politics as a student at Balliol College, Oxford, where he studied for a BA and came to know Christopher Hitchens, then himself active in the International Socialists (the SWP's forerunner).

[citation needed] Callinicos participated in the Counter-Summit to the IMF/World Bank Meeting in Prague, September 2000 and the demonstration against the G8 in Genoa, June 2001.

[citation needed] Callinicos was a critic of the humanitarian interventions in Bosnia and Kosovo, arguing that they were conducted solely to promote the global capitalist expansion.

[7] He called the allegation of rape a "difficult disciplinary case",[7] a comment for which socialist feminist Laurie Penny thought he "[mistook] a plea for some basic respect for women's sexual autonomy as an attempt to undermine the revolution from within.