Background Blunt chest injury leads to significant morbidity and mortality. The aim of this study was to evaluate the effect of a multidisciplinary chest injury care bundle (ChIP) on patient and health service outcomes. ChIP provides guidance in three key pillars of care for blunt chest injury-respiratory support, analgesia and complication prevention. ChIP was implemented using a multi-faceted implementation plan developed using the Behaviour Change Wheel. Methods This controlled pre-and post-test study (two intervention and two non-intervention sites) was conducted from July 2015 to June 2019. The primary outcome measures were unplanned Intensive Care Unit (ICU) admissions, non-invasive ventilation use and mortality. Results There were 1790 patients included. The intervention sites had a 58% decrease in non-invasive ventilation use in the post- period compared to the pre-period (95% CI 0.18-0.96). ChIP was associated with 90% decreased odds of unplanned ICU admissions (95% CI 0.04- 0.29) at the intervention sites compared to the control groups in the post- period. There was no significant change in mortality. There were higher odds of health service team reviews (surgical OR 6.6 (95% CI 4.61-9.45), physiotherapy OR 2.17 (95% CI 1.52-3.11), ICU doctor OR 6.13 (95% CI 3.94-9.55), ICU liaison OR 55.75 (95% CI 17.48-177.75), pain team OR 8.15 (95% CI 5.52 -12.03), analgesia (e.g. patient controlled analgesia OR 2.6 (95% CI 1.64-3.94) and regional analgesia OR 8.8 (95% CI 3.39-22.79), incentive spirometry OR 8.3 (95% CI 4.49-15.37) and, high flow nasal oxygen OR 22.1 (95% CI 12.43-39.2) in the intervention group compared to the control group in the post- period. Conclusion The implementation of a chest injury care bundle using behaviour change theory was associated with a sustained improvement in evidence-based practice resulting in reduced unplanned ICU admissions and non-invasive ventilation requirement.