Forty-one pre-service elementary teachers (PSETs) enrolled in a science methods course participated in a service-learning project on energy and sustainability. The goal was to help PSETs and elementary students to understand concepts regarding energy, energy saving, and sustainability through an oncampus Family Energy Day event for 65 elementary school students. PSETs participating in the service-learning project identified gains in science knowledge, an increased awareness of their own energy saving practices, the relevancy of the activities, and how the project helped shape their professional identity as strengths. Elementary students who participated also showed commitment to practicing a variety of energy saving habits which they were exposed to through the event. Strengths of the service-learning experience for both PSETs and elementary students included the opportunity to learn in an informal environment, the development and use of activities related to both groups' daily lives, and the opportunities the event presented for real-wold application and reciprocal learning.