Immobility in the intensive care unit (ICU) is associated with neuromuscular weakness, post–intensive care syndrome, functional limitations, and high costs. Early mobility–based rehabilitation in the ICU is feasible and safe. Mobility-based rehabilitation varied widely across 5 ICUs in 1 health care system, suggesting a need for continuous training and evaluation to maintain a strong mobility-based rehabilitation program. Early mobility–based rehabilitation shortens ICU and hospital stays, reduces delirium, and increases muscle strength and the ability to ambulate. Long-term effects include increased ability for self-care, faster return to independent functioning, improved physical function, and reduced hospital readmission and death. Factors that influence early mobility–based rehabilitation include having an interdisciplinary team; strong unit leadership; access to physical, occupational, and respiratory therapists; a culture focused on patient safety and quality improvement; a champion of early mobility; and a focus on measuring performance and outcomes.