Sports betting is a burgeoning although potentially harmful leisure pursuit among young men. Young men are a vulnerable group for developing harmful gambling behaviors, yet little is known around drivers of their sports betting participation. Informed by self-determination theory (SDT), qualitative data were collected via in-depth interviews and focus groups with Australian men ages 18–34. Sports betting was driven by individualized, interrelated webs of motives reflecting five SDT behavioral regulations, geared around satisfying innate psychological needs of relatedness and competence. While autonomous motivation was noted, environmental factors generating controlled motivation appeared significant in stimulating the young men’s sports betting as they sought to construct social identities in the context of hegemonic Australian cultural ideals. This research contributes nuanced insights into young men’s sports betting motivations and sets out a future research agenda.