During the early phase of the COVID-19 pandemic (March 2020-August 2021), the Province of Ontario enacted restrictions and recommendations that changed over time. We assessed individual and systemic factors shaping behaviours and contributing to exposure risk during this time. Participants across all age groups and health statuses adapted their behaviours in response to evolving regulations but older individuals and those with pre-existing conditions had the largest change in behaviour and when they developed COVID-19 or other influenza-like illnesses, had the most severe symptoms. Our analysis underscores the responsiveness of exposure risk to government-imposed restrictions, with increased stringency coinciding with decreased exposure risk among participants. These findings collectively emphasize the interplay between demographic factors and government interventions in shaping individual behaviours over the course of the pandemic. Understanding these dynamics is crucial for informing targeted interventions and mitigating the impact of future pandemics.