This study explored the impact of incorporating interactive elements of YouTube, such as commenting and engagement, within social media-integrated writing activities. The aim was to examine how this approach influences the writing anxiety and writing performance of Korean English as a Foreign Language (EFL) learners. The participants, all of whom were first-year students at an intermediate English level, consisted of 115 EFL students. Among them, 58 were assigned to the experimental group, while the remaining 57 were part of the control group. The experimental group actively participated in social media-integrated writing activities that emphasized YouTube commenting and interactive engagement, while the control group engaged in traditional writing activities. Data collection involved pre- and post-writing tasks, accompanied by a pre- and post-questionnaire measuring second language (L2) writing anxiety. The findings revealed that the inclusion of YouTube commenting and interaction within social media-integrated writing activities was considerably more effective than traditional writing activities in reducing writing anxiety and enhancing writing proficiency. Specifically, the experimental group exhibited significant improvements in writing proficiency compared to the control group, and this improvement was observed across multiple dimensions including content, coherence, vocabulary, grammar, and mechanics. Additionally, the experimental group experienced a notable reduction in writing anxiety. These results highlight the importance of integrating interactive elements, such as YouTube commenting and engagement, in EFL writing instruction to alleviate writing anxiety and enhance writing proficiency among EFL learners. Furthermore, this approach offers innovative opportunities for language learning within educational settings.