Canada implemented the legalization of nonmedical cannabis use and supply in 2018. Initial blueprints for the legalization policy framework emphasized public health protection as a priority principle and objective, including related policy design parameters and regulatory restrictions (e.g., strict access and distribution control, advertisement/promotion ban, etc.) also as informed by adverse experiences from alcohol/tobacco control. Conversely, Canada's present legalization ecology is characterized by increasingly far‐reaching commercialization; this includes an extensive for‐profit cannabis production and retail industry producing large sales volumes that centrally include high‐risk cannabis products, with many public health‐oriented provisions hollowed out or circumvented in practice. While key cannabis‐related health problem indicators have increased through legalization, mounting evidence suggests that these adverse outcome dynamics, to a crucial extent, have been accelerated by commercialization aspects of legalization. Meanwhile, since legalization the cannabis industry has pushed for further rollbacks of public health‐oriented restrictions for benefits of increased competitiveness. Using the Canadian case study, we focus on the possible pitfalls and adverse effects of commercialization dynamics for public health‐oriented cannabis legalization. Also since commercialization‐related developments and outcomes are hard to reverse, we urge jurisdictions planning cannabis legalization reforms to carefully take consider related evidence and dynamics when assembling their legalization policy frameworks.