This study explores the effectiveness of media literacy-based activities on writing proficiency and affective domains in the EFL setting. A quasi-experiment was conducted during the 2021 academic year with 148 college EFL students selected as participants from three classes from a private university in Seoul, South Korea. Participants were divided into three groups based on proficiency levels: upper proficiency, intermediate proficiency, and lower proficiency. The assigned activities included four steps: (1) watching video clips made by a teacher, (2) group discussion, (3) individual presentation, and (4) individual writing. For these activities, participants used multimedia like YouTube, Fanfiction.net, Reddit discussion boards, and blogs to understand the topic, evaluate the content, and express their thoughts. Popular franchises, including the Marvel Cinematic Universe (MCU), the Potterverse, and the Twilight saga provided material for the activities. The study’s results reveal that students significantly increased their writing skills, regardless of proficiency level. Moreover, the higher the linguistic ability, the more the writing ability improved. In a survey, students also showed significant changes in all affective domains (anxiety, interest, confidence, and engagement), except for the lower proficiency group’s confidence domain. The study presents a detailed summary of the activities and derives meaningful implications.