IntroductionPhysical activity, healthy eating and maintaining a healthy weight are associated with reduced risk of cardiovascular disease, type 2 diabetes and cancer and with improved mental health. Despite these benefits, many men do not meet recommended physical activity guidelines and have poor eating behaviours. Many health promotion programmes hold little appeal to men and consequently fail to influence men’s health practices. HAT TRICK was designed as a 12-week face-to-face, gender-sensitised intervention for overweight and inactive men focusing on physical activity, healthy eating and social connectedness and was delivered in collaboration with a major junior Canadian ice hockey team (age range 16–20 years). The programme was implemented and evaluated to assess its feasibility. This article describes the intervention design and study protocol of HAT TRICK.Methods and analysisHAT TRICK participants (n=60) were men age 35 years, residing in the Okanagan Region of British Columbia, who accumulate 150 min of moderate to vigorous physical activity a week, with a body mass index of >25 kg/m2 and a pant waist size of >38’. Each 90 min weekly session included targeted health education and theory-guided behavioural change techniques, as well as a progressive (ie, an increase in duration and intensity) group physical activity component. Outcome measures were collected at baseline, 12 weeks and 9 months and included the following: objectively measured anthropometrics, blood pressure, heart rate, physical activity and sedentary behaviour, as well as self-reported physical activity, sedentary behaviour, diet, smoking, alcohol consumption, sleep habits, risk of depression, health-related quality of life and social connectedness. Programme feasibility data (eg, recruitment, satisfaction, adherence, content delivery) were assessed at 12 weeks via interviews and self-report.Ethics and disseminationEthical approval was obtained from the University of British Columbia Okanagan Behavioural Research Ethics Board (reference no H1600736). Study findings will be disseminated through academic meetings, peer-reviewed publication, web-based podcasts, social media, plain language summaries and co-delivered community presentations.Trial registration numberISRCTN43361357,Pre results