This study aims to explore how the realization of experiential metafunction varies depending on the genre in elementary school students' writing. Among the various functions of language, experiential metafunction focuses on the way human experience is represented in language. Various human experiences appear in different lexicogrammars; however, the same experience can also be realized in different lexicogrammars. The ability to properly regulate experiential metafunction can be one of the key factors in subjective language use. In addition, it was necessary to check whether the language of actual learners varies depending on the genre, as the genre concept has recently played a diverse role in organizing the contents of Korean language education system. We collected sample writings of explanations, arguments, and emotional expressions among school-age learners from fifth graders in elementary school, and analyzed them according to the transitivity profiling procedure, which allowed us to calculate the frequency of process types and participant type patterns. Statistical validation was conducted with genre as the main variables. As a result, in six of the nine process types, 17 of the 74 participant type patterns were able to identify significant differences. These differences require additional qualitative interpretation. In this work, we note that there are significant differences in the participant type patterns of writing explanations and emotional expressions while equally choosing the verbal process. In the explaining writing, the sayer was not realized as much as in the writing expressing emotions, and there was a tendency to nominalize the speech content rather than direct citation through projections. In the future, other school-age learners studies should explore how genre variations affect the realization of experiential metafunction and qualitatively interpret the mechanisms that influence the linguistic choices of fifth graders.