|Testosterone governs most facets of reproduction in vertebrates, and its effects on behavior and sexually selected traits have been documented in many species. We evaluated annual and lifetime patterns of circulating serum testosterone in a freely breeding population of white-tailed deer (Odocoileus virginianus) in Alabama across 10 years. Although this region experiences peak breeding roughly 2–3 months later than most white-tailed deer populations in the U.S., we found peak testosterone levels coincide with the height of the breeding season for our population. Testosterone was positively associated with antler and body size only until age 6.5. Antler size, but not testosterone, was associated with annual reproductive success. Additionally, there were differences in lifetime patterns of testosterone between individuals, which may relate to differences in lifetime reproductive strategies. This suggests testosterone plays an indirect role in reproductive success through its relationship with antler size and may relate to lifetime patterns of reproductive investment.