Workplaces offer a key setting for health improvement interventions, given their reach and potential to promote lasting behaviour change. While diet and physical activity (PA) are common targets, sleep remains an underexplored yet influential factor in employee health. This randomised feasibility trial evaluated the practicality and acceptability of a 14-week, remotely delivered sleep-enhanced intervention (SEI) integrating sleep, PA, and diet, compared with a standard intervention (SI) focusing on PA and diet only, with exploratory assessment of behavioural and health-related outcomes. Staff from a UK higher education institution (n=28) with short sleep duration (<7 hours) and elevated cardiometabolic risk were randomised to SEI or SI. Quantitative data included self-reported and objective measures of PA, sleep, diet, and anthropometry over 14 weeks. Feasibility outcomes (recruitment, retention, compliance) and acceptability were assessed through qualitative interviews informed by the Theoretical Framework of Acceptability (TFA). Recruitment targets were achieved with 82% retention and 84% adherence. The SEI group showed indications of improvement in PA, dietary behaviours, anxiety symptoms, and sleep hygiene, while both groups showed reductions in body mass index and waist circumference. Qualitative data highlighted the value of personalised guidance, peer support, and accountability, but also noted that the SEI’s complexity sometimes hindered adherence. The WHOLE trial demonstrates the feasibility and acceptability of a remotely delivered, holistic lifestyle intervention for UK employees. A phased or extended approach may enhance sustainability and engagement in future large-scale evaluations.