Knysna louries clamber around in trees, hopping from branch to branch in search of fruit and seeds, which they swallow whole. They exist usually in pairs or small family groups, and noisily defend their territory with a hoarse 'kow-kow' noise.

The nest of a knysna lourie is an untidy affair built in the thickest part of a tree from interlocking sticks and twigs. The entire structure is about 20 to 30 cm (8 to 12 in) in diameter. Although two white eggs are laid, usually only one nestling survives.