The development of radical Islamic understanding amongst abangan society is a paradox because there is a dichotomy between santri and abangan. This study aims to describe and analyse the transformation of preman or thugs into members of the radical Islamic army in Solo, Central Java. This research reveals why Solo is the base of a radical Islamic Laskar, how premans are predisposed to become members of the Islamic Laskar, and the types of radical Islam of this former preman. This type of research uses qualitative methods and a descriptive phenomenology approach with the social construction theory from Peter L. Berger and Thomas Luckmann. The results reveal that the rise of radical Islamic Laskar organisations is because of the local conditions of the community life in Solo. They are the leaders of Islamic troops, as an essential role of agents is to lead the social construction of preman to become members of the Laskar. Meanwhile, the type of Islamic radicalism of the preman was categorised as pseudoradicalism and fake radicalism.Contribution: This research contributes to the study of radicalism formed by religious organisations. This study describes and analyses in depth the transformation of the preman into members of the radical Islamic army in the city of Solo and the base of the radical Islamic Laskar. The most important finding of this article is the Islamic radicalism of the preman, which is categorised as pseudoradicalism and fake radicalism.