Background/Objectives: To describe the Mobility Action Group (MACT), an innovative process to enhance implementation of hospital mobility programs and create a culture of mobility in acute care. Design: Continuous quality improvement intervention with episodic data review. Setting: Inpatient units including medical, surgical, and intensive care settings. Participants: A total of 42 hospitals of varying sizes across the United States. Interventions: The MACT and Change Package were developed to provide a conceptual framework, road map, and step-by-step guide to enable mobility teams to implement mobility programs successfully and meet their mobilization goals. Participants were encouraged to select two to three change tactics to pursue during the first action cycle and select and implement additional tactics in subsequent cycles. Nine learning sessions were held via webinar from April 27, 2017, to October 5, 2017, during which faculty provided brief presentations, facilitation, and group discussion. Measurements: Implementation of programs, walks per day, use of bed and chair alarms, and participant satisfaction. Results: Successful implementation of mobility programs was achieved at most (76%) sites. The proportion of patients who received at least three walks per day increased from 9% to 19%. The proportion of patients who were placed on a bed or chair alarm decreased from 36% to 20%. On average, 69% of participants reported they were “strongly satisfied” with the learning sessions. Most participants found the Change Package (58%) and Toolkit (63%) “very helpful.” Since the conclusion of the active initiative, the Change Package has been downloaded 1,200 times. Of those who downloaded it, 48% utilized it to establish a mobility program, and 58% used it at their organization at least once a month. Conclusion: The MACT and Change Package provides an innovative approach emphasizing systemwide change that can help catalyze a culture of mobility in hospitals across the nation, improving the quality of care for hospitalized older adults. J Am Geriatr Soc 68:2373–2381, 2020.