This study explored the attitudes of 31 English majors toward, and the knowledge constructed through, the design and implementation of glocalized English lessons as service learning, and reached the following major findings. First, theme- and topic-based lessons with contextualized dialogues were designed through the reciprocal investigation of the textbooks and local features, however, the glocalization was not fully integrated into listening and speaking activities and hands-on activities. Secondly, the TESOL method course, instructor’s modeling, and collaborative lesson planning purposefully prepared 31 English majors for the design and implementation of lessons as service learning. The competence of 31 English majors was constructed through experiential actions and reflective practice, particularly in the curriculum, pedagogy, and knowledge of learners, and they had positive attitudes toward such service learning.