In this paper, we explore how the pressure to deliver high performance influences line managers in their shaping and repurposing of employee voice mechanisms to encourage improvement‐oriented voice in organizations. Using qualitative data (50 semi‐structured interviews) from two case studies, including a manufacturing organization and a university, we find line managers were proactive in the (re)shaping and repurposing of employee voice mechanisms in response to the high‐performance strategy. Where there was less HR support given to line managers, we found line managers were more inclined to create their own voice mechanisms. However, we observed that a focus on improvement‐oriented voice associated with employer interests diverted employee‐interest voice away from collective and formal channels, into more informal channels. We indicate the dangers of prioritizing an employer‐interest, improvement‐oriented voice approach.