Drawing upon 40 life-history interviews with gang members in Medellín, Colombia, this paper argues that many young men join gangs to emulate and reproduce ‘successful’ local male identities. The accumulation by the gang of ‘masculine capital’, the material and symbolic signifiers of manhood, and the accompanying stylistic and timely displays of this capital, means that youths often perceive gangs to be spaces of male success. This drives the social reproduction of gangs. Once in the gang, the youths become increasingly ‘bad’, using violence to defend the gang's interests in exchange for masculine capital. Gang leaders, colloquially known as duros or ‘hard men’, tend to be the más malos, the ‘baddest’. The ‘ganging process’ should not be understood in terms of aberrant youth behaviour; rather there is practical logic to joining the gang as a site of identity formation for aspirational young men who are coming of age when conditions of structural exclusion conspire against them.