"Saurophaganax" was one of the largest carnivores of Late Jurassic North America. Chure even gave an estimate of , though other estimations have been lower. The fossils known of "Saurophaganax" (both the possible New Mexican material and the Oklahoma material) are known from the Brushy Basin Member, which is the latest part of the Morrison Formation, suggesting that this genus was either always uncommon or that it first appeared rather late in the Jurassic. "Saurophaganax" was large for an allosaurid, and bigger than both its contemporaries "Torvosaurus tanneri" and "Allosaurus fragilis". Being much rarer than its contemporaries, making up one percent or less of the Morrison theropod fauna, not much about its behavior is known.