BACKGROUND: Early mobilization is important to improve critically ill patients’ outcomes, but barriers to its implementation are common. A suitable in-bed device to exercise patients’ legs might facilitate early mobilization. OBJECTIVE: The aim of this study was to develop an in-bed leg press that would facilitate early mobilization and enhance strength training of patients in acute care settings. METHODS: A user-centered design approach was applied to develop the device. The process was assessed by different instruments: the system usability scale (SUS) questionnaire, the Kano model questionnaire and interviews with end-users. RESULTS: Through several iterations of a user-centered design process, the prototype of an in-bed leg press was developed and tested. The assessment, based on SUS, Kano and interviews, indicates high usability and demonstrates the advantages of a user-centered design process. CONCLUSIONS: An interprofessional user-centered design approach was successfully implemented to develop a medical device. The early involvement of end-users resulted in a design that already shows a high degree of production readiness. The resulting device fulfilled all core requirements from a therapeutic point of view and included key features related to its practical use.