Older patients receiving antineoplastic treatment face challenges such as frailty and reduced physical capacity and function. This systematic review and meta-analysis aimed to evaluate the effects of exercise interventions on physical function outcomes, health-related quality of life (QoL), and symptom burden in older patients above 65 years with hematological malignancies undergoing antineoplastic treatment. This review adheres to Cochrane guidelines, with the literature searches last updated on 27 March 2024, including studies with patients above 18 years. Screening of identified studies, data extraction, risk of bias, and GRADE assessments were performed independently by two authors. Meta-analyses evaluated the impact of exercise, considering advancing age. Forty-nine studies contributed data to the meta-analyses. Five studies included patients with a mean age above 60 years, and none included only patients above 60. Exercise interventions had moderate to small positive effects on QoL global (SMD 0.34, 95% CI [0.04–0.64]) and physical function (SMD 0.29, 95% CI [0.12–0.45]). Age did not explain the variability in exercise effects, except for physical function (slope 0.0401, 95% CI [0.0118–0.0683]) and pain (slope 0.0472, 95% CI [0.01–0.09]), which favored younger patients. Exercise interventions improve physical function and QoL and reduce symptoms in adults with hematological malignancies undergoing antineoplastic treatment; however, the influence of age remains inconclusive.