This study examined the linguistic and methodological issues that arose as two Korean professors taught their subject matter in English to Korean college students and how each professor used the comments and suggestions provided by a teacher trainer. The participants included two Korean female professors who taught their major course in English. The data came from the analysis of the two professors’video-recorded lessons, the teacher trainer’s notes of follow-up discussions with each professor, and students’ response to the surveys. The results showed that the two Korean EFL professors exhibited more methodological than linguistic issues as they delivered their subject matter in English. Additionally, the way they used the trainer’s comments on their instruction revealed differences. One professor closely followed them, thereby changing her future instruction, whereas the other did not pay close attention to them; consequently, her subsequent lessons showed little transformation from her first lesson. This study suggests that it is important to establish a systematic support system for Korean EFL content professors who deliver their lesson in English.