This article examines the political, social and psychological experiences of a group of young working-class men who in the early-to-mid 1960s became active members in branches of the Labour Party Young Socialists. Concentrated in London's East End, these branches had become increasingly open to the politics of International Socialism, a tiny libertarian Trotskyist group that provided these young men with a political education and a social circle, and propelled them into a bourgeoning activist network. Activism in their groups occurred at a crucial moment of personal and political transition – social maturation from child to adult intersected with the formation of a new and distinctive extra-parliamentary culture on the British left that came to full fruition around Britain's anti-war movement, the Vietnam Solidarity Campaign. The formation of this collection of inner lives occurred simultaneously in the context of real social and economic shifts in the men's local landscapes as well as the wider international Cold War climate. Drawing upon oral history interviews with former Young Socialist members, this article explores the cultural and social expression of these working-class men, looking at subjectivity and gender to understand how their sub-culture provided for childhood structures of feeling and early class identity and to consider what meaning they derived from active socialist involvement.