Most previous studies of language and gender have focused on English as well as women’s language. The present study focuses on context dependency and the multiple functions of Japanese men’s language, or “masculine Japanese.” It reports a case study that qualitatively analyzes four conversations between a Japanese male and a female speaker collected in a naturalistic setting. The findings suggest the specific nature of the mixed-gender pair is important in examining these aspects. In mixed pairs where the male speaker is in a superior position to the female speaker, his use of masculine Japanese may be limited in “direct talk” or when he is directly addressing his female interlocutor because of their relatively hierarchical interpersonal relationship. On the other hand, his use of masculine language may be more frequent in direct quotations used to reveal his inner thoughts or simulate male speakers’ speech from prior contexts during his storytelling. In each context, masculine Japanese seems to have different functions. In direct talk, it provides linguistic resources for constructing traditional masculinities, even if they are not necessarily used, for example, when his relative status is a more salient feature than his gender. By contrast, in direct quotation, masculine language may be used as an involvement strategy or to consolidate solidarity, thus constructing different dimensions of interpersonal relationships in the mixed pair, though it may also be used as an entertainment strategy. The paper also discusses the need for a more holistic approach by including interactional features in research on gender and Japanese language.