Despite the increasing prevalence of online health information seeking (OHIS) among older adults, its impact on patient-centered communication (PCC) outcomes remains unclear. Drawing from Street’s ecological framework of communication in medical encounters, the present study examined the mediation role of patient activation in the relationship between OHIS across three media channels–social media, search engines, and mobile health applications (mHealth apps)–and PCC. Furthermore, it examines the moderation effect of patient-provider discussions of online health information. A national survey of 916 older Chinese adults aged 60–78 was conducted. The findings indicate that OHIS across the three channels can indirectly enhance PCC through patient activation. Moreover, OHIS via mHealth apps is positively associated with PCC, while the relationship between OHIS via social media/search engines and PCC is not significant. The interaction between patients and healthcare providers regarding online health information positively moderated all indirect paths. Notably, a great proportion of older adults (77.7%) engaged in discussions about online health information with healthcare providers. These findings emphasize the importance of considering various media channels and highlight the pivotal role of patient activation in bridging the gap between OHIS and satisfactory healthcare interactions, especially in the Chinese context.