Greenspace exposure has been linked to various health outcomes, but evidence for cancer remains scarce and inconsistent. Few longitudinal studies have incorporated time-varying measures of greenness, cancer subtypes, and comprehensive adjustment for confounders. We investigated the long-term effects of greenspace exposure on cancer mortality, incidence, and survivorship in the U.S. NIH-AARP Diet and Health Study. We included 417,148 cancer-free participants enrolled in 1995–1996 and followed through 2011. Residential greenness was quantified using the Normalized Difference Vegetation Index (NDVI) from Landsat images with 30 m X 30 m spatial resolution and linked to participants at the census tract level. Cox proportional hazards models with time-varying exposures were used to capture changes in greenness over time, adjusting for demographic, socioeconomic, and behavioral factors (age, sex, race/ethnicity, education level, smoking history, physical activity level, and BMI). Survival time was calculated for each cancer outcome (mortality, incidence, and survivorship) for obesity-related cancers. Among cancer patients, individuals with higher exposure to green spaces had a lower mortality risk from all-types of cancer and lung cancer, with hazard ratios of 0.87 (95% CI: 0.79–0.95) and 0.92 (95% CI: 0.89–0.96), respectively. We provided large-scale longitudinal evidence on whether long-term residential greenspace exposure is associated with cancer mortality, incidence, and survivorship across multiple cancer sites. Our findings are expected to inform urban planning and public health policies that seek to leverage greenspace as a potential component of cancer prevention and survivorship support in aging populations.