This study aims at exploring the types, meaning and functions of syntactic presupposition triggers employed in narration about Gatsby and Daisy's characters in Fitzgerald's The Great Gatsby. It adapts a model proposed by Li (2010) and Du (2012) based on the theory of presupposition by Levinson (1983) and Yule (1996). Through the descriptive qualitative approach, the data analysis shows that all six types of syntactic triggers studied are found, the most frequently employed triggers are the non-factive adverbial clauses, and the least frequently employed ones are questions. The analysis also brings into light the descriptive, narrative, thematic and symbolic purposes of these triggers along with their various functions. The results detect that Fitzgerald uses presupposition to portray the outstanding features in his characters and stress the themes of the disillusionment of the American Dream and the improbability of repeating the past, portraying the inescapable sorrowful demise of his own dreams.