The reality is that most students and teachers have multiple, complex, and even contradictory identities. This matters greatly because it's hard for young people to succeed or be well if they feel they need to hide significant parts of themselves because their identities are stigmatized for being different or stereotyped to fit into a program or a category. So, the urgent question is this: Can schools help students flourish in the fullness of their identities? The authors believe the answer is yes -- if education professionals can get beyond categorizing people because of one characteristic that supposedly supersedes all others, whether it be race, gender identity, privilege, disability, or something else. By acknowledging and embracing complexity, education professionals can make identity a vital foundation for inclusion, achievement, and equity in education. With these considerations in mind, this article draws on two research programs -- in collaboration with 10 school districts and with a national network of 41 schools attempting innovation for greater inclusion after COVID-19 -- to examine the complexity of students' identities and what it means for rethinking professional learning and development.