The Southern Grey-headed Sparrow inhabits savanna, woodlands, plantations, agricultural areas and suburbs where it feeds mainly on seeds, fruit, nectar and insects and is often seen in association with other kinds of seed-eating birds, including the very similar Cape Sparrow. Grey-headed Sparrows weigh about 24g and grow to around 15cm in length.
Pairs are monogamous and usually breed well away from others of their kind, although they do form flocks outside the breeding season. Both parents work together to construct the nest, a simple aggregation of matted grass, leaves, stems, hair and feathers in holes in trees, under roofs or in the abandoned nests of other birds. The breeding season stretches from spring to autumn, reaching a peak in summer. The parents take turns to incubate the clutch of 2-6 eggs over a period of 2 weeks. The chicks leave the nest at between 2 and 3 weeks old and remain dependent on their parents for another 3 weeks or so thereafter.
In South Africa, Grey-headed Sparrows can be found in all provinces, representing a rapid range expansion aided by their ability to exploit human habitations for food and nesting. Today, Southern Grey-headed Sparrows are only absent from portions of the arid Northern Cape. Apart from South Africa they are also found in Lesotho, Swaziland, Namibia, Botswana, Zimbabwe, Mozambique, Angola, Zambia, Malawi and Tanzania. The IUCN considers this species to be of least concern.