Phylogenetic analyses suggest that Smilosuchus is more closely related to mystriosuchins than to Leptosuchus species.

The rostral crest and nasal bulge supporting these raised nostrils was larger in Smilosuchus than in many other phytosaurs.

The jaws are very short and broad and the teeth are heterodont, with large tusks at the anterior of the mouth for impaling prey and more blade-like teeth for slicing flesh closer to the back of the mouth.

The tusks are mounted on a bulge at the tip of the snout present in nearly all phytosaurs.

Its squamosal processes are short and deep, indicating a powerful bite.