Because of the rapid expansion of computer science (CS) education, educational leaders must consider how to recruit, prepare, and support teachers who typically do not have a background in CS. This study examines two professional development (PD) approaches used to introduce CS education to non-CS teachers. We aim to understand if/how each model promoted teacher agency in CS--conceptualized as the interactions between individual teacher confidence and broader conditions of support and constraints. Drawing on both survey data and qualitative data, we found that teachers who participated in a curriculum-based PD benefited from more practical applications of CS versus focusing on the theoretical principles of CS education. These findings carry important implications for other districts aiming to develop non-CS teachers to deliver CS instruction.