Physogaleus secundus was a small requiem-shark relative with a low cutting dentition. It belonged to the early carcharhinid radiation and probably occupied a versatile predatory role in warm coastal and shelf waters.

Its asymmetrical teeth formed an efficient slicing and gripping edge rather than the tall piercing dentition of many lamniform sharks. Small fishes and invertebrates are the most plausible prey, with the shark likely taking whatever manageable food was locally available.

The species is known mainly from isolated teeth, so its precise body form and behaviour remain uncertain. Its dentition nevertheless records an increasingly modern-looking carcharhiniform feeding style within the diverse early Eocene shark fauna.