This paper provides a Distributed Morphology analysis of the paradoxical interaction of the two cases of verbal suppletion in Korean, and argues that the two suppletion types are characterized by two different types of morphological operations. The two roots found with short-form negation and honorification suggest different morphological structures: [[Neg-V] Hon] for al- ‘know’, molu- ‘not.know’, a-si- ‘know-hon’, molu-si- (not *an(i) a-si-) ‘neg know-hon’; and [Neg [V-Hon]] for iss- ‘exist’, eps- ‘not.exist’, kyey-si- ‘exist-hon’, an(i) kyey-si- (not *eps-(u)-si-) ‘neg exist-hon’. Predicate repetition constructions support the [[Neg-V] Hon] structure. In this structure, however, the negative suppletion (analyzed as fusion of negation and the root) is blocked by the honorific suffix structurally more peripheral to the root. C-command is the only requirement for context allomorphy in Distributed Morphology (Halle & Marantz 1993). Since the [+hon] feature c-commands the root, the root can show honorific suppletive allomorphy in the first cycle with negation intervening between the root and [+hon]. Negation fusion occurs in the second cycle after vocabulary insertion of the root. Fusion, then, should refer to vocabulary items, not abstract features, and will be interleaved with vocabulary insertion. If the output of the root is /kyey/ due to the honorific feature, negative suppletion will not apply and the correct form an(i) kyey-si- will be derived. Therefore, both of the distinct morphological operations for suppletion, i.e., fusion and contextual allomorphy, are necessary. The revised formulation of fusion shows that certain morphological operations follow vocabulary insertion. This derivational approach to the suppletion interaction provides support for separation of phonological and nonphonological features and for late insertion of phonological features.