The Brown Honeyeater is found in a wide range of wooded habitats, usually near water. It is often found in mangroves and woodlands or dense forests along waterways. It can also be found in mallee, spinifex woodlands, low dense shrublands, heaths and saltmarshes
The Brown Honeyeater feeds on nectar and insects, foraging at all heights in trees and shrubs. It may be seen in mixed flocks with other honeyeaters. In Western Australia, these include the Singing Honeyeater, White-fronted Honeyeater and the Red Wattlebird, while in the Top End it is often seen with the Dusky Honeyeater. However, it will be displaced at bird feeders by larger birds.
During the breeding season, male Brown Honeyeaters defend a nesting territory by singing from tall trees and they stand guard while the female builds the nest and lays the eggs. The small neat cup-nest is made from fine bark, grasses and plant down, bound with spiders web, and is slung by the rim in a shrub, fern or tree at up to 5 m from the ground and is usually very well-hidden by thick foliage. Only the female incubates, but both sexes feed the young.