This study investigated the associations between in-person and remote engagement and self-rated happiness in older adults aged 50 years and above in three cognitive function subgroups: Normal Cognition, Cognitive Impairment not Dementia (CIND), and Dementia. Data were obtained from the 2014 Health and Retirement Study. Results showed that remote engagement was significantly associated with higher self-rated happiness, particularly in the CIND group. However, its association with in-person engagement was less consistent. No significant association was observed among individuals with dementia. However, the direction of the relationship between the two types of social engagement and self-rated happiness was positive. Instrumental activities of daily living, depression, and social capital were identified as potential factors influencing the relationship between social engagement and self-rated happiness. These findings emphasize promotion of both in-person and remote social engagement opportunities to enhance the well-being of older adults across different cognitive function subgroups.