Preventing/Countering Violent Extremism (P/CVE) interventions are largely based on theories that young people (especially young men) are particularly vulnerable to radicalisation leading to violent extremism. Youth is seen as a vulnerable time of identity formation, separation from family and openness to other influences. However, too much focus on youth as a driver of extremism misses the existence of older participants in extremist violence, clouds understanding of the reasons for their violent acts and neglects an important demographic in P/CVE. In this article, we challenge the “youth radicalisation” thesis which underpins so much P/CVE work and argue that such work needs to acknowledge the existence of older militants who experience long-term and intergenerational engagement with violent movements. We do this through analysis of a series of interviews with 11 older men (and 6 family members), from Ireland/Northern Ireland and Bosnia and Herzegovina, who have been involved in violent extremism. The reasons for their involvement are found to lie in family and community cohesion across interconnected generations in contexts of political conflict. The findings therefore challenge the automatic connection of youth and radicalisation and so call into question P/CVE initiatives which are only youth centric. Instead, it is essential to create interventions based on theories of change that understand intergenerational cohesion, grievances in sectarianised contexts and political interrelationships between states and communities.