The shifting topography of contemporary Japanese society is engendering a significant reorientation of men’s family relations. However, exactly how Japanese men are adapting to these broad-based trends, including parent-child relations, demographics, marriage norms, care provision, residential choices, and gender roles, as well as in the decline of Confucian worldviews, remains relatively obscure. In this dissertation, I explore men’s everyday practices underpinning their family relations as husbands, fathers, sons-in-law, and grandfathers. I conducted ethnographic fieldwork in the summers of 2013 and 2014 in Hyogo, through narrative interviews and participant-observation. I find husbands’ view of their wives transitioning from having a culturally prescribed duty to perform domestic matters to simply having responsibility for domestic matters. This opens up space for negotiation within married couples, with my informants providing what I refer to as additional help, which offers new insight into charting the evolution of hegemonic masculinity. I evidence relatedness founded on exchange as an approach to understand relations across the extended family, which importantly involves additional help, financial resources, and intimacy. I underscore how men selectively seek intimacy in some family relations, notably as fathers and grandfathers. Provision of additional help and seeking of intimacy lead to men’s (re)construction of masculinities differing across family relations, with an important reason for men to select their practices so as to craft their family relations is to address their sense of well-being. Further, the pattern of men’s family relations reveals the emergence of substantially novel sons-in-law relations, as compared to that found in ie patriarchal norms. This evidence suggests a fundamental shift from a vertically-dominated set of family relations, as in the ie household, to a more horizontal, fluid set of relations across the extended family.