Ecological worldviews, or deep mental patterns and habitual ways of looking at our relationship to the natural world, can be influenced by environmental education (EE). In forest preschool, which is an immersive environmental education strategy, children draw closer to the natural world through nature play. Nature play serves as an ecological identity development process that can be studied to explore and define children’s individual and collective relationships to their environment. In this case study, narratives were collected from teachers, children, and mothers to explore the indicators of ecological identity development in children at a forest preschool in Baltimore City, Maryland. Four main ecological identity indicators emerged from the data. The children at Wild Haven Forest Preschool developed an ecological identity during nature play by making nature connections, mastering their bodies, feeling part of the forest preschool community, and using movement and senses. The most memorable naturalist relationships for children were hiking, making elemental observations, identifying flora, and experiencing biophilia. Children used nature to master their bodies through risky play like tree climbing. They experienced a deep sense of community through playing and making friendships. Their movement and senses focused on campfires, water, snow, and hills. The findings from this study inform environmental education in that they support the hypotheses of biophilia and topophilia; reveal the role of risky play in children’s ecological identity development; provide a procedure template for ecologically-centered assessment of children in forest immersion programs; inspire guidelines for curriculum development; and provide families with an academic resource describing their child’s attitude toward nature.