The patent utilization performance of public research institutions in Korea, including universities and government-funded research institutes, has often been criticized as low relative to R&D investment. However, there is limited empirical evidence on how intellectual property (IP) management capabilities translate into patent utilization outcomes, particularly regarding the relationship between internal personnel and external services. This study examines the effects of internal IP staff and external IP services on patent utilization rates across 239 public research institutions, using data from the 2024 Intellectual Property Activities Survey. Given the fractional and censored nature of patent utilization rates, Tobit regression models were employed to estimate both main and interaction effects. The results show that internal IP staff are positively and significantly associated with patent utilization rates, whereas the contribution of external IP services depends on the level of internal IP capabilities. Specifically, external IP services meaningfully contribute to patent utilization in institutions with limited internal IP staff, whereas their role is adjusted as internal IP capacity expands. These findings suggest that internal IP capabilities moderate the impact of external IP services on patent utilization performance, underscoring the importance of strategically aligning internal capacity building and external service utilization according to an institution’s stage of IP capability development.