Integrated STEAM education in South Korea is an approach to preparing a quality STEM workforce and literate citizens for highly technology-based society. Through a literature review, this study examined the STEAM education initiative in South Korea and investigated its effects on learning and teaching. Studies in South Korea found that teacher professional development courses increased teachers' recognition of the initiative as well as their confidence in teaching STEAM. Teacher interviews showed that coaching in classroom practices within teachers' professional development was helpful. Although studies reported that many science teachers adopted STEAM in science teaching, there was a lack of research on how teachers taught STEAM lessons, let alone the connections between teachers' perceptions of STEAM and their classroom practices. As for STEAM effects on student learning, a number of meta-analyses showed that students' experiences with STEAM were effective in both cognitive and affective learning. The effect was higher in affective domains. Interviews with college students who had STEAM experiences in grade school showed that the effects could be long-term. The meta-analysis studies failed to identify significant mediating factors, which required further in-depth research on how contextual variables function in student learning. This paper provides a glimpse of what can be achieved through STEAM efforts, and what should be further researched for better theory and practice.