This study aimed to identify the correlation between influencing factors of activities of daily living (ADLs), mental health, and health-related quality of life (HRQoL) among post-stroke patients who enrolled in a transitional care service in a public hospital. This cross-sectional study involved 67 stroke patients who were enrolled in a transitional care service and visited the outpatient clinic at a public hospital in Seoul between March and December 2022. Their general characteristics, ADLs, mental health, and HRQoL were assessed. The data were analyzed using independent samples t-tests, analysis of variance, and Pearson correlation analysis, and the influencing factors were analyzed using regression analysis. HRQoL showed a statistically significant difference between patients living in different types of arrangements (t = 2.50, p = 0.015), and patients scores on the modified Rankin Scale (t = 7.08, p < 0.001). HRQoL was also significantly correlated with ADLs and mental health in stroke patients (r = −0.59, p < 0.001; r = −0.41, p < 0.001, respectively). Meanwhile, stroke severity (β = −0.30, p = 0.002), living arrangements (β = −0.30, p = 0.009) and ADLs (β = −0.45, p < 0.001) were found to influence HRQoL (F = 6.87, p < 0.001, R
2
= 0.47). Reduced dependence for ADLs, improvements in symptoms consequent to stroke, and support related to living arrangements contributed to improved HRQoL and interventions for post-stroke patients in the transitional care service of a public hospital.