Degenerative cerebellar ataxias (DCAs) are progressive diseases that reduce quality of life (QoL). This study aimed to assess the impact of rehabilitation on QoL in patients with DCAs using structural equation modeling (SEM). This cross-sectional survey included members of a national Japanese DCAs patient association. Assessed latent variables included personal, medical, and environmental factors, impairments, activity limitations, rehabilitation (participation quantity and patient-reported quality), and QoL. SEM was used to explore causal relationships between these latent variables. Overall, 477 participants (mean age 65.4 years; 45.1% female) were included. Impairments were categorized as primary and secondary, based on preliminary analyses. The final model demonstrated acceptable-to-good fit indices, explaining 74% of the variance in QoL. The model paths showed that activity limitations, secondary impairments, and rehabilitation quality had a direct effect on QoL, in that order. The quantity of rehabilitation had an indirect effect on QoL through its direct effect on secondary impairments and quality of rehabilitation. These findings suggest that rehabilitation interventions improve QoL in the DCA population, but its effects vary depending on the quantity and quality of rehabilitation. However, the cross-sectional study design limits the ability to draw causal conclusions and longitudinal studies are needed for confirmation.