Platycephalus laevigatus was first formally described in 1829 by the French zoologist Georges Cuvier with the type locality given as Western Port in Victoria.

The background colour is greenish to pale brown flathead marked with darker bars across the back.

It occurs on rocky reefs, sand and seagrass beds in coastal waters down to at least 20 m (66 ft).

[4] Platycephalus laevigatus, unlike many of its congeners prefers to resting on the hard substrate in areas of sea weed and seagrass, rather than burying itself in the sediment.

[4] Platycephalus laevigatus is of minor importance to commercial fisheries and is landed in small numbers using beach seines and gillnets.