With the goal of supporting educators in bringing more playful learning into their classrooms and schools, the Pedagogy of Play USA project conducted research in six schools in the Boston area in the Northeastern United States (U.S.). Considering the specific challenges and affordances of the local educational context, we examined what playful learning looks and feels like. Based on our research, we found that playful learning in the classrooms we studied is empowering, meaningful, and joyful. We begin this working paper with an example from a 2nd grade math lesson, one of three examples we share throughout the paper that illustrate what playful learning can look and feel like. Then, we explain the importance of understanding what playful learning involves in U.S. schools, describe the qualitative research methods employed in this work, and introduce the Indicators of Playful Learning: Six United States Schools, a model of what learning through play looks and feels like in the six schools in this study. We conclude with a discussion of the relevance of the indicators model to other U.S. schools. In Appendix A, we share examples of online playful learning in 1st and 5th math instruction.