The Golden-breasted Bunting builds an untidy cup nest lined with fine grass or hair low in a shrub or sapling. The 2–3 eggs are glossy white or cream and marked with black lines. The eggs hatch in 12–13 days and the chicks fledge in another 16–17 days.
The Golden-breasted Bunting is not gregarious, and is normally seen alone, in pairs or small groups. It feeds on the ground on seeds, insects and spiders, animal prey being taken mostly when the birds have young. This species is generally resident, but there appears to be degree of local movement. It is often quite tame.