Purpose – Research on patient safety campaigns has mostly concentrated on large-scale multi-organisation efforts, yet locally led improvement is increasingly promoted. The purpose of this paper is to characterise the design and implementation of an internal patient safety campaign at a large acute National Health Service hospital trust with a view to understanding how to optimise such campaigns. Design/methodology/approach – The authors conducted a qualitative study of a campaign that sought to achieve 12 patient safety goals. The authors interviewed 19 managers and 45 frontline staff, supplemented by 56 hours of non-participant observation. Data analysis was based on the constant comparative method. Findings – The campaign was motivated by senior managers’ commitment to patient safety improvement, a series of serious untoward incidents, and a history of campaign-style initiatives at the trust. While the campaign succeeded in generating enthusiasm and focus among managers and some frontline staff, it encountered three challenges. First, though many staff at the sharp end were aware of the campaign, their knowledge, and acceptance of its content, rationale, and relevance for distinct clinical areas were variable. Second, the mechanisms of change, albeit effective in creating focus, may have been too limited. Third, many saw the tempo of the campaign as too rapid. Overall, the campaign enjoyed some success in raising the profile of patient safety. However, its ability to promote change was mixed, and progress was difficult to evidence because of lack of reliable measurement. Originality/value – The study shows that single-organisation campaigns may help in raising the profile of patient safety. The authors offer important lessons for the successful running of such campaigns.