In recent discourse-oriented studies of grammar, it has been claimed that the information structure of discourse is composed of two levels, foreground and background, and that linguistic categories such as tense and aspect have as their functions the sorting of information into these two levels. However, this study of Korean narrative finds that Korean tense and aspect distinguish not between foreground and background, but between ordinary and significant information within foreground and background. It was found that a total of five levels of information are signalled by the choice of tense and aspect in Korean narrative: ordinary background information, significant background information, ordinary mainline events, significant mainline events, and peak.Ordinary background information is indicated by the imperfective aspects (progressive, resultative, continuative, iterative, and inchoative) with the past tense. Significant background information is indicated by either the progressive the resultative with the historical present tense. The completive or inceptive aspects, both of which are perfective, combine with the past tense to mark ordinary mainline events. These shift to the progressive or resultative with the historical present to indicate significant mainline events. Peak is indicated by the completive aspect as well as tense-shift and other stylistic and linguistic devices such as onomatopoeia, concentration of participants, change of the normal pace of the story, or change from narration to dialogue. Tense and aspect are thus interrelated in signalling function and degree of significance of information.This study demonstrated two major points. First, Korean distinguishes five levels of information in narrative discourse. Second, these are differentiated by the choice of tense and aspect, among other devices. Two methodological consequences are that linguistic categories such as tense and aspect may be fully analyzed only in a discourse-based study and that mode of discourse cannot be analyzed without reference to tense and aspect.