It is found in Costa Rica, Panama, and every mainland South American country except Argentina, Chile, Paraguay, and Uruguay.

[2] The population in Central America and western Colombia and Ecuador, has at times been treated as the subspecies M. m. extimus, but this separation has not been widely recognized.

Their throats and underparts are white to cream, and plain but for a few dark feather shafts making streaks.

Juveniles have dark brownish gray upperparts and off-white to yellowish buff underparts with a scaly appearance.

It mostly inhabits lowland rainforest, favoring undisturbed areas, but also occurs in mature secondary forest and sometimes in rather open landscapes.

The slaty-backed forest falcon's primary vocalization is a "chanting series of 8-13 nasal, shouting kiiih or kaaah notes".