Since the founding of UC Santa Cruz in 1965, first-year undergraduate students have enrolled in a class called Core: a seminar offered by their college that introduces students to the theme of the college and, in recent decades, college-level writing. Beginning in Fall 2018, Core was reformed into a new course called College 1. Unlike Core, College 1 focuses on academic reading rather than writing and includes a common set of learning outcomes designed around the “ACMES:” analysis, critical thinking, metacognition, engagement across difference, and self-efficacy. This dissertation examines the implementation of College 1 from the perspectives of the instructors who first taught it in Fall 2018. Drawing from interviews, classroom observations, and an original survey, I examine how instructors understood the College 1 learning outcomes and taught these in their classrooms. This study sheds light on the process of implementing curricular change in higher education and, more broadly, on how individuals’ sensemaking shapes change in institutions. Three main findings emerged from this study: College 1 instructors tended to adopt explicit, implicit, or oppositional approaches to teaching the course learning outcomes; instructors’ classroom practices were related to their sense of autonomy over their classes; and a central challenge articulated by instructors was the integration of Chinese international students into their untracked classes. From these findings, I offer practical recommendations for future professional development trainings for College 1 instructors.