Major surgery in older adults is increasingly common as life expectancy rises and advances in surgical, anesthetic, and intensive care practices expand treatment options for this population. However, conventional surgical outcomes do not fully reflect the complexity of recovery in older patients. Psychological and neurocognitive complications represent frequent, clinically meaningful, and often under-recognized determinants of postoperative recovery. Older adults undergoing coronary artery bypass grafting, valve surgery, aortic and major vascular procedures, thoracic surgery, abdominal oncologic surgery, and hip fracture repair are particularly vulnerable to postoperative delirium, perioperative neurocognitive disorders, depression, anxiety, sleep disturbances, post-traumatic stress symptoms, and post-intensive care syndrome. The development of these complications is multifactorial, involving interacting biological factors (neuroinflammation, cerebral hypoperfusion, and systemic stress responses), patient-related clinical factors (frailty, pre-existing cognitive impairment, pain, and polypharmacy), environmental and healthcare-related factors (intensive care exposure, sensory deprivation, and sleep disruption), and psychosocial factors (social isolation, emotional distress, and psychological stress associated with life-threatening illness). This narrative review integrates evidence from diverse surgical populations to provide a comprehensive framework linking preoperative vulnerability, perioperative insults, and postoperative psychological and neurocognitive outcomes. Beyond summarizing existing knowledge, this review proposes a patient-centered model of surgical success that extends beyond survival and technical outcomes to include preservation of cognition, emotional well-being, sleep recovery, functional independence, and return to meaningful daily activities. By integrating geriatric, surgical, anesthetic, and psychological perspectives, this review highlights the need for a multidimensional approach to evaluating outcomes after major surgery in older adults.