There is a growing body of literature on leadership and leadership development across the early years sector. Early years leadership research has so far tended to focus on positional leadership demonstrated by setting managers or preschool room leaders. There is a notable gap in the understanding of the role of the baby room leader, leading practice for children from birth to two, and how leadership can be developed in this specific context. Drawing on a design workshop with baby room leaders and nursery managers, as well as five follow-up semi-structured interviews with baby room leaders, this article offers an insight into the role of the baby room leader, with a particular focus on everyday advocacy. It presents four advocacy themes in baby room leadership: (1) highlighting and understanding the impact of baby room practice; (2) sharing a passion for working with babies; (3) advocating professional development specific to the baby room; and (4) challenging the discourses and stereotypes surrounding those who work in the baby room. These themes represent both current realities in baby room leadership and opportunities for future development and mobilisation.