Aims: Involvement in minor drug offences at an early age can be a signal of the onset of a potential drug issue. This is why Sweden has considered the criminalization of personal use as a strategy to deter the progression of drug use. This study investigated how the judiciary and social services succeed in identifying and providing support to adolescents convicted of drug offences. Methods: Characteristics of all 15–17-year-olds convicted of offences against the Act on Penal Law on Narcotics (drug offence) in 2017 were examined using Swedish longitudinal registry data (N = 1847). Furthermore, the decision process rendering different legal responses was examined by use of social services files for a subsample of 189 adolescents. Results: About two-thirds of the adolescents had their first conviction for the index offence and the majority received legal responses consisting of rehabilitative measures. Background factors indicated that those with severe drug and criminal issues encounter risk factors relating to their upbringing (e.g., neuropsychiatric disorders were notably more prevalent in this group than among similar peers). Around 61% of adolescents were reconvicted for new drug offences during the three-year study period, but with variations among subgroups. Younger boys who received rehabilitative measures had lower reconviction rates compared to those without. Conclusions: Addressing the underlying factors contributing to adolescent drug offences requires a multifaceted approach that prioritizes early intervention, personalized support, and collaboration across systems to promote positive outcomes and reduce recidivism rates.