There is a broad range of literature on individuals who mediate at the boundaries between science and policy. However, there seems to be little empirical evidence on the goals and strategies of knowledge brokers, even though they appear to be becoming increasingly important in the field of environmental science and policy. This paper aims to improve the understanding of why and how knowledge brokers operate through an analysis of 27 in-depth interviews. It demonstrates that they see themselves as (strategically) sensitive to all stakes and stakeholders involved, possess a large network, and act without interests. They appear to act strategically in two different settings: on stage, where the collaboration of all stakeholders is needed, and backstage, where the knowledge broker steers the process on his/her own. Furthermore, our research suggests that the (perceived) credibility and legitimacy of the knowledge broker is more important to the process than the degree of credibility and legitimacy of the knowledge used in the decision-making process, and that it would be advisable to deploy knowledge brokers proactively, instead of reactively, which could lead to 'incident politics'.