<p>A growing body of research demonstrates the salience of particular crosscutting concepts (CCCs) in supporting science learning within and across disciplines. However, there is a need for research on how learning experiences support student sensemaking of the CCCs over time. With its emphasis on careful observation of natural phenomena, identifying patterns, and asking questions, nature journaling may hold particular promise as a technique to support learning of the CCCs. Through a single, exemplary case study, we examine how one learner used her exploration of phenomena to arrive at the CCCs as she constructed knowledge through nature journaling over a period of two-and-a-half years. Findings revealed that the process of nature journaling supported certain CCCs over others, and that particular strategies and techniques fostered increasing understanding of the CCCs. In addition, integrating the CCCs with science core ideas and practices contributed to the learner’s sensemaking regarding the CCCs; as her disciplinary knowledge grew, her engagement with the CCCs became more sophisticated, and she was also more inclined to use science practices to explore phenomena. Using experiential learning theory as a framework, we unpack the experiences that supported this process, including consistent interaction with the natural world, iterative and recursive reflection, and close mentoring by a nature journaling expert. With this case we demonstrate the affordances of nature journaling for supporting sensemaking of concepts that cut across many of the scientific disciplines.</p>