Background Weapons and drug offences incur a large cost to society and tend to be strongly associated. Improved understanding of their antecedents could inform targeted early intervention and prevention programmes. Aim This study aimed to examine differences in criminal careers, childhood predictors and adolescent correlates among weapons‐only offenders, drugs‐only offenders and a versatile group of weapons + drugs offenders. Method We conducted a longitudinal records study of 455 young Canadians charged with drug and/or weapons offences who started their offending in late childhood/early adolescence. Results Consistent with expectation, differences emerged in their criminal careers as the versatile group had a longer criminal career and desisted from offending at a later age than weapons‐only offenders. Against prediction, weapons‐only offenders experienced the greatest number of childhood predictors and adolescent correlates. Conclusion and implications for practice The three offending groups could be differentiated on offending trajectories and developmental factors.In making links between past events and later behaviour, life‐course criminology may inform development of effective early intervention and prevention strategies.As weapons‐only offenders experience the greatest level of adversity in childhood and adolescence, they may benefit most (of these three groups) from early intervention and prevention programmes.A reduction in weapon carrying and use might be achieved by early identification of children risk factors (e.g. family adversity) and appropriate intervention. Copyright © 2013 John Wiley & Sons, Ltd.