<p>Supporting first-generation college students in their transition to elite universities has become a critical issue in global higher education. Using student agency theory in higher education and the concept of “mesosystem” from the ecological system theory, this longitudinal qualitative study explores how Chinese first-generation college students exercise student agency during their first-year transition to elite universities and examines the role of the university environment in shaping this process. Three patterns of agency are identified: (1) navigating coursework through learning habits cultivated in high school, (2) expanding social connections within the university to interpret the “hidden curriculum,” and (3) setting feasible academic and career goals to regain direction beyond the college entrance exam. The study also identifies three conditions under which students exhibit restrained agency: (1) “stickiness” in test-taking contexts, (2) identity anxiety and self-exclusion from selective opportunities, and (3) self-concealment amid conflicting expectations from family and university. The exercise of agency is shaped by meso-level institutional structures, including exam-assessed first-year curricula and a GPA-centered student evaluation system, collectivist organizational practices and peer interaction norms, and university-led value advocacy aligned with national imperatives to cultivate “top-notch innovative talents.” By analyzing how these agentic patterns interact with the distinctive institutional logics of Chinese elite universities, the study highlights how student agency is fostered and constrained in ways that differ from Western neoliberal contexts. Based on these findings, the study advocates for reforms in institutional practices and national policies to ensure first-generation college students’ success beyond mere admission to elite universities.</p>