George Gilchrist made innumerable contributions to evolutionary biology and ecology through his research, mentorship, and service to the National Science Foundation. I will highlight all of these dimensions of George’s work through the example of his impact on my own development as a scientist and the arc of my research program. In particular, I will focus on the evolutionary ecology of thermal plasticity, a field of great interest to George to which he made many significant advances. I will cover the following themes: 1) how thermal plasticity evolves at broad spatial scales, 2) the benefits of plasticity in dynamic environments, and 3) constraints on the expression and evolution of plasticity.