The Sooty-headed Tyrannulet forages in the canopy and subcanopy of humid montane forest. Peru Aves says its range is poorly understood and lists records in Peru, Colombia, Ecuador, and Brazil.
The adult description has an olive back and gray crown, with a pale eyebrow and a faint eye-ring. A dusky stripe runs from the bill base through the eye; the throat is gray, the breast olive, and the rest of the underparts yellow.
It forages in the canopy and subcanopy of humid montane forest and tall second growth. The account gives an approximate elevation of 1,500 m but says the range is poorly understood.
An extinction-risk assessment has not been added yet.