Queensland experienced relatively low case numbers during the first year of the coronavirus disease 2019 (COVID-19) pandemic. This may be due to timely, stringent policies, yet there is currently no research evaluating this link, despite the state government playing such a primary role in the pandemic response. This ecological study used a cross-sectional design to examine the stringency and timeliness of Queensland's containment policies and their impact on COVID-19 cases in 2020. To achieve this, the authors generated a stringency index for Queensland in 2020 in line with the Oxford COVID-19 Government Response Tracker (OxCGRT) method, since these data were not available at the time. The national context was also provided by examining the relationship between case numbers and policies in Australia. The findings demonstrated a statistically significant relationship between policy stringency and case numbers in both Australia and Queensland. While Australia experienced two waves of COVID-19 in 2020, Queensland only experienced one. In terms of timeliness, there was a reactive approach to the first wave, with rapid escalation of policy stringency in both Queensland and Australia as a whole. Queensland's ability to prevent a second wave in 2020 may be due to a more systematic, gradual de-escalation of policies and the maintenance of strategies such as interstate border controls. This study suggests that preventing the reintroduction of new cases after a period of elimination is important. Recommendations are made for the application and interpretation of the stringency index. Further research is needed to understand the relationship between de-escalation strategies and outcomes.