The Red-legged Seriema is distributed from central and eastern Brazil through eastern Bolivia, Paraguay and Uruguay into central Argentina. It is found in open woodland, grassland and other open areas such as chaco, caatinga and cerrado.

They feed on beetles, grasshoppers, lizards, snakes and rodents as well as grain. Its main strategy to escape predators is to run very fast occasionally flying awkwardly for short distances.

There is some doubt as to its exact relationship with other bird families but it is generally included with the Cranes Gruiformes. Superficial similarities to the Secretarybird Sagittarius serpentarius should be put down to convergent evolution.