The concept of Total Quality Management (TQM) has come to be applied in healthcare over the last few years. The process management category in the Baldrige Health Care Criteria for Performance Excellence model is designed to evaluate the quality of medical services. However, a systematic approach for implementation support is necessary to achieve excellence in the healthcare business process. The Architecture of Integrated Information Systems (ARIS) is a business process architecture developed by IDS Scheer AG and has been applied in a variety of industrial application. It starts with a business strategy to identify the core and support processes, and encompasses the whole life-cycle range, from business process design to information system deployment, which is compatible with the concept of healthcare performance excellence criteria. In this research, we apply the basic ARIS framework to optimize the clinical processes of an emergency department in a mid-size hospital with 300 clinical beds while considering the characteristics of the healthcare organization. Implementation of the case is described, and 16 months of clinical data are then collected, which are used to study the performance and feasibility of the method. The experience gleaned in this case study can be used a reference for mid-size hospitals with similar business models.