This study aims to empirically examine the structural relationships among liberal-arts reading habits, reading metacognition, and research competency among graduate students, and, based on the findings, to discuss implications for university library research support. An online survey of 157 Korean graduate students was conducted. Data were analyzed using correlation, ANOVA, and bootstrap-based mediation analysis (PROCESS Macro Model 4). Three key findings emerged. First, liberal-arts reading habits were extremely strongly correlated with reading metacognition (r=.851, p<.001), which in turn significantly correlated with research competency (r=.596, p<.001). Second, although the total effect of reading habits on research competency was significant (B=.308, p<.001), the indirect effect through metacognition (ab=.246) was statistically insignificant, as its 95% confidence interval included zero ([-.039, .462]). This null result is attributed to multicollinearity and insufficient discriminant validity arising from their high correlation, suggesting that reading and metacognitive self-regulation function as an inseparable, integrated cognitive mechanism rather than sequential stages. Third, reading metacognition differed significantly by degree program (F=4.70, p=.010, η²=.058). Doctoral students (n=13) reported lower metacognitive self-assessments than master’s students, possibly reflecting cognitive humility accompanying growing research proficiency. Given that a sequential mediation structure could not be confirmed, this study tentatively proposes, at an exploratory level, that reading metacognition may function as a key cognitive resource linking liberal-arts reading and research competency. Based on these findings, this study suggests, as an implication, that university libraries may need to move beyond their role as mere “information providers” toward functioning as “cognitive support environments,” tentatively proposing divergent reading support for master’s students, advanced metacognitive regulation support for doctoral students, and the fostering of research-oriented reading communities.