Discourse marker jiéguǒ (DM jiéguǒ) has three usages in Present-Day Chinese, i.e., the temporal usage, the causal usage, and the counter-expectation usage. It evolved from nominal jiéguǒ in the 1920s, with the temporal usage as the starting point. Two recent changes are that counter-expectation dm jiéguǒ has become movable as to its syntactic position and that temporal dm jiéguǒ can be used as an independent utterance when combined with sentence-final particle ne. In this study, the developmental path of dm jiéguǒ is divided into five stages. Different from the grammaticalization hypothesis proposed in the previous literature, the genesis and development of dm jiéguǒ is analyzed as the output of cooptation and late grammaticalization.