The pale-blue monarch is endemic to eastern Indonesia. It has two subspecies. The nominate race, Hypothymis puella puella, is found on Sulawesi and adjacent islands, and Hypothymis puella blasii is found in the Banggai archipelago. Both forms are often considered to be subspecies of the widespread black-naped monarch (Hypothymis azurea).
The pale-blue monarch is a forest species which builds a small cup nest. It has short legs and sits very upright whilst perched prominently, like a shrike. It is insectivorous, often hunting by flycatching.