ObjectivePsychological support skills training has the potential to improve both the ability of cancer staff to help their patients, and staff wellbeing. However, few recent studies have assessed both these outcomes or incorporated current developments in psychological skills training, such as deliberate practice, which includes the use of iterative, corrective feedback to identify and improve individualised skill deficits. No studies have evaluated the contribution that psychological skills training could make to cancer care staff wellbeing and expertise in the wake of the COVID‐19 pandemic. This study aimed to evaluate staff skill acquisition and work‐related wellbeing following psychological support skills training that applied deliberate practice principles.MethodA 2‐day training and monthly supervision was offered to 145 cancer care staff that focused on brief assessment and intervention skills for patients experiencing mental health problems after cancer diagnosis and treatment. Deliberate practice principles were used to focus training on skills practice and feedback, over technique description. Self‐reported ability to perform key skills taught, staff mental wellbeing, work engagement, and burnout were assessed at baseline, 3‐month and 8‐month follow‐up.ResultsSignificant improvements in skills, mental wellbeing, burnout and work engagement were reported at 8‐month follow‐up. Full engagement in both training sessions was predicted by poorer baseline mental wellbeing, more positive evaluation of initial training, supervision attendance, and shorter follow‐up.ConclusionA 2‐day psychological support skills training using deliberate practice principles may support improvement in staff skill, mental wellbeing, burnout and work engagement.