Environmental and natural resource economics lies inherently at the interface between economic and natural dynamics (e.g., geological constraints, climate change, biodiversity evolution). Building models in that field often means building integrated models, calling on knowledge and methods from economics and physics, climatology, biology, or ecology. Howard Scott Gordon’s 1954 article on fishery economics is considered to be seminal in the history of bioeconomic modeling, integrating biological and economic variables in a microeconomic model. Yet the precise role played by biology in Gordon’s initial work remains unclear. On the basis of archival material and thorough analysis of Gordon’s early research, this paper examines Gordon’s model building and his persistent oscillation between two objectives—the production of a heuristic economic model with standard assumptions, and the conception of a predictive policy tool relevant from a fishery-biology standpoint—and how he finally favored the first over the second. Moreover, contrary to received wisdom, we show that it was not Gordon but biologist Milner B. Schaefer who transformed Gordon’s model into an integrated model. These results shed new light not only on Gordon’s 1954 contribution but also on a whole tradition of integrated environmental and natural resource economics models, based on his work.