Objectives: To develop a system-based intervention including five components that target barriers to nurse-initiated patient ambulation. Design: Pilot study of Mobilizing Older adult patients VIa a Nurse-driven intervention (MOVIN). Setting: Twenty-six bed general medical unit. Participants: Nursing staff (registered nurses and certified nursing assistants) were recruited to participate in focus groups. Measurements: Information on frequency and distance patients ambulated and nursing staff documentation of patient ambulation were retrieved from the electronic medical record. Regression discontinuity analysis was used to determine a difference between the preintervention and intervention periods in ambulation occurrence, ambulation distance, and percentage of numeric documentation of ambulation. Thematic analysis was used to analyze focus group interviews. Results: A statistically significant increase in number of occurrences (t = 4.18, P =.001) and total distance (t = 2.75, P =.01) and a significantly higher positive slope in percentage of numeric documentation was found during the intervention than before the intervention. Thematic analysis identified three central categories (shifting ownership, feeling supported, making ambulation visible) that describe the effect of MOVIN on nursing staff behaviors and perceptions of the intervention. Conclusion: Decreasing loss of independent ambulation in hospitalized older adults requires new and innovative approaches to addressing barriers that prevent nurse-initiated patient ambulation. MOVIN is a promising system-based intervention to promoting patient ambulation and improving outcomes for hospitalized older adults.