Background: Delivery of cardiovascular disease (CVD) prevention programs by community pharmacists appears effective and enhances health service access. However, their capacity to implement complex behavioural change processes during patient counselling remains largely unexplored. This study aims to determine intervention fidelity by pharmacists for behavioural components of a complex educational intervention for CVD prevention. After receiving training to improve lifestyle and medicines adherence, pharmacists recruited 70 patients aged 50–74 years without established CVD, and taking antihypertensive or lipid lowering therapy. Patients received five counselling sessions, each at monthly intervals. Researchers assessed biomedical and behavioural risk factors at baseline and six months. Pharmacists documented key outcomes from counselling after each session. Most patients (86%) reported suboptimal cardiovascular diets, 41% reported suboptimal medicines adherence, and 39% were physically inactive. Of those advised to complete the intervention, 85% attended all five sessions. Pharmacists achieved patient agreement with most recommended goals for behaviour change, and overwhelmingly translated goals into practical behavioural strategies. Barriers to changing behaviours were regularly documented, and pharmacists reported most behavioural strategies as having had some success. Meaningful improvements to health behaviours were observed post-intervention. Findings support further exploration of pharmacists’ potential roles for delivering interventions with complex behaviour change requirements.