In this article we share the theoretical framework of threshold concepts--concepts on which deep understanding of a field of practice and inquiry hinges and which, once understood and internalized, open a doorway to otherwise inaccessible ways of thinking--and explore its relevance to learning how to teach, learn, serve, partner, and generate knowledge through service-learning. We extend the focus of work on threshold concepts beyond student disciplinary learning to faculty pedagogical learning, in particular to learning about service-learning; and we contribute to theory on how threshold concepts are learned by developing the idea of threshold experiences--reflective encounters with dissonance that give rise to deeper understanding and sometimes internalization of threshold concepts. In line with the exploratory nature of this piece, we use an example of an instructor learning a threshold concept in service-learning through a threshold experience to ground our extension of current work on threshold concepts, our consideration of implications, and our identification of questions for ongoing inquiry. Examining faculty learning through the lens of threshold concepts and threshold experiences can help us understand, address, and embrace dissonance-related challenges and opportunities involved in learning the whys and hows of service-learning pedagogy.