Big data is expected to provide many benefits to healthcare organizations through cost reduction, disease prediction, and patient care improvement. Big data in healthcare at a nascent stage faces many challenges in satisfying expectations. This study investigates factors for promoting the implementation and usage of big data in healthcare in Korea, using an analytical hierarchy process (AHP). We established a research framework that considers four domains and 15 factors. We collected data by a survey of experts engaged in big data and healthcare IT. The results show that data and organization have greater impacts than technology and support domains. Organizational analytics capability, data quality, data privacy and security, organizational application capability, data standardization, and data experts are the most important factors for promoting the implementation and usage of big data in healthcare. The study presents the implications in terms of the policies and ecosystem for countries, including Korea, which intend to activate big data in healthcare.