Older adults with cancer heterogeneously experience health care, treatment, and symptoms. Geriatric assessment (GA) offers a comprehensive evaluation of an older individual's health status and can predict cancer-related outcomes in individuals with solid tumors and those with hematologic malignancies. In the last decade, randomized controlled trials have demonstrated the benefits of GA and GA management (GAM), which uses GA information to provide tailored intervention strategies to address GA impairments (e.g., implementing physical therapy for impaired physical function). Multiple phase 3 clinical trials in older adults with solid tumors and hematologic malignancies have demonstrated that GAM improves treatment completion, quality of life, communication, and advance care planning while reducing treatment-related toxicity, falls, and polypharmacy. Nonetheless, implementation and uptake of GAM remain challenging. Various strategies have been proposed, including the use of GA screening tools, to identify patients most likely to benefit from GAM, the systematic engagement of the oncology workforce in the delivery of GAM, and the integration of technologies like telemedicine and mobile health to enhance the availability of GA and GAM interventions. Health inequities in minoritized groups persist, and systematic GA implementation has the potential to capture social determinants of health that are relevant to equitable care. Caregivers play an important role in cancer care and experience burden themselves. GA can guide dyadic supportive care interventions, ultimately helping both patients and caregivers achieve optimal health.