This species feeds on a varied diet, including arthropods, hemipterans, small amphibians, and occasionally fruits. It is typically seen alone or in pairs, rarely joining mixed-species flocks. Attila cinnamomeus perches quietly and makes slow, cautious movements before quickly darting short distances to catch prey from branches or foliage. Both parents take part in feeding the young and are particularly attentive during the early stages of development.

Attila cinnamomeus thrives in seasonally flooded forests like várzeas and igapós, as well as permanently swampy areas of the Amazon. It also inhabits wet plantations, palm-dominated areas, mangroves at river deltas, lake edges, river islands, and along streams and rivers.

We found nests in Caseara, Tocantins (2 nests).

In Tocantins, breeding occurs from October to February. Other records show nesting activity in December (Mato Grosso and Pará) and January (Rondônia).

Their nests are built using plant material gathered from tree bases and riverbanks, often after the water recedes. Nests can also frequently be found in palm trees, small cavities, and under bromeliads. One nest was built on an old machine and another on a solar panel battery, showing flexibility in site choice and that the species adapts well to both natural and human-made structures. The nest structure is made of clumped vegetation mixed with moss and dry mud.