In many countries, growing deer populations cause environmental, economic, and traffic safety problems. This study sheds light on the potential implications of expanding the consumption of venison from hunted wild deer through deer population management efforts. It focuses on changes in environmental impacts resulting from changes in the demand for livestock meat due to increased consumption of wild venison. We analyzed the demand system between them using the Quadratic Almost Ideal Demand System (QUAIDS) model and scanner data from a grocery store chain in Hokkaido Prefecture, Japan. The results show that wild venison is a substitute good for pork and lamb. By contrast, wild venison is a complementary good for imported and domestic beef. Based on the estimated demand system model, we conducted an environmental footprint analysis to estimate the changes in environmental impacts when venison consumption increased. This shows that the greenhouse gas, water, and land footprints would increase, indicating greater environmental impacts, under a scenario of expanded venison consumption. The results demonstrate that increased venison consumption does not necessarily reduce the net environmental impacts of meat consumption, which depends on the demand system for meat products and the environmental footprint intensities of the respective products.