Smart Classroom Management (SCM) is an approach proposed by Linsin (2013) that takes into account students' needs and interests in class. It has four main strategies: Planning, Organization, Leadership, and Control. This study investigated experimentally the role of English as a Foreign Language teachers' use of SCM in response to learners' second language (L2) anxiety, engagement (behavioral, emotional, and cognitive), and language achievement. To gauge the students' L2 anxiety, six items out of the Dörnyei's (2005) L2 Motivational Self System were used. To measure student engagement, the Student Engagement Scale (SES) was employed. To conduct the research, a mixed methods design (integrating experimental and interview methods) was utilized. In the experimental phase, two classes at the same level were selected. In the experimental group, a treatment that was prepared based on SCM strategies was utilized. In the qualitative phase, four students of the experimental class were voluntarily interviewed about the effects of using SCM strategies on their learning. The results demonstrate that using SCM strategies as a treatment, that was prepared based on students' needs and a humanistic approach, had a significant impact on learners' engagement and its subscales up to 46%. Moreover, applying SCM was influential in reducing students' L2 anxiety and enhancing language achievement. The findings of this study are expected to inspire policy makers, teacher educators, and supervisors to facilitate the implementation of SCM in language classes.