The purpose of this study is to examine the critical incidents experienced by preliminary Korean language and literature teachers in the course of practicing their education expertise. For this, this study has selected 48 college students majoring in Korean language and literature education at K University as study subjects and collected and analyzed descriptions of critical incidents experienced while practicing. The analysis results have been able to classify critical incidents experienced by preliminary Korean language and literature teachers while practicing in class into several categories, including teaching behaviors, student guidance, and guidance teachers. First, preliminary Korean language and literature teachers were able to understand the complexity of the on-site classroom while experiencing the process of organizing knowledge, functions, and attitudes that they are well aware through the critical incidents as to teaching behaviors in line with the context of the classroom environment. Next, critical incidents regarding student guidance have served as an opportunity for teachers to contemplate upon their qualifications as a teacher. Finally, ‘critical incidents with regards to the guidance teacher have served as an occasion for teachers to build insights into education by solidifying the practical knowledge while understating the education phenomenon and pondering about desirable educational acts.