As Indigenous-led education mandates proliferate globally, understanding how educators teach Indigenous perspectives and sovereignty remains urgent. Learning and integrating such knowledge proves difficult for non-Native teachers, given their lengthy participation in settler colonial schooling and society. What does learning to implement Native sovereignty curriculum entail? Codesigned with eight Native education leaders, this qualitative study examines five non-Native K-12 teachers' learning processes with Washington's Since Time Immemorial curriculum across three schools, using interviews, observations, and other data. Findings indicate six themes of learning supporting meaningful implementation, one potential catalyst for overall growth, and two distinct learning trajectories that suggest outward, rather than inbound, directionality. Implications for teacher education and educational leadership clarify needed steps for teacher learning and curriculum implementation.