A substantial literature has developed around the individual determinants of radical political preferences. Widely used to study electoral support for far-right parties, this perspective has rarely been mobilised to understand the dynamics of radicalisation, or the process of going back to the ‘roots’, among fractions of Western Muslim youth involved in political Islam. To address this, 37 semi-structured interviews were conducted between 2020 and 2021 as part of ongoing ERC Advanced Grant research with young (aged 18–30) self-identifying Muslims of Turkish and Moroccan descent based in the Paris or Lyon areas. Also drawing on the social movements literature, we uncovered two sets of factors influencing radicalisation, each based on two distinct oppositional sets of attitudes: (1) a feeling of estrangement from mainstream societal values, such as morality, secularism, and a perceived assimilationist trend emanating from the French national frame, and (2) a sense of dissatisfaction towards the political-institutional system, which appeared as latent criticisms of the current state of representative democracy, distrust of political and media actors, and discontent towards the current French party system.