This article considers the formal teacher leaders' practices of leading knowledge development at the department level in early childhood education and care. To better understand these practices, we have utilised the hybrid leadership theory, along with qualitative shadowing and stimulated recall interviews. Our analyses demonstrate that these teacher leaders encourage knowledge development by functioning as hybrid leaders in their communities of practice, while our findings show that there are four leadership approaches to knowledge development that emerge from everyday work: providing professional guidance, acting as a role model in work performance, putting practices into words and supporting desired teaching practices. Moreover, our study reveals that the leading of knowledge development is dependent on teacher leaders' practical knowledge and their influence in their communities of practice. We therefore posit that the provision of knowledge development through and within the relationships that comprise communities of practice is crucial developing ECEC as learning organisations.