[1] From 1965 to 1991, Brain directed the Transvaal Museum, which became one of the most scientifically productive institutions of its kind in Africa during his tenure.
Very early in Brain's career, Robert Ardrey wrote of him: [In 1958] I was spending a night in a South African village with a party of scientists.
He had followed this with three fruitful years in anthropology, in which time he had furnished palaeontology with its only comprehensive geological survey of all five australopithecine sites; had developed techniques of ancient dating never thought of before by anyone; and with his uncovering of primitive stone handaxes at Sterkfontein had made a discovery ranked by Dr. Kenneth P. Oakley of the British Museum as one of the anthropological milestones of the century."
Although Brain retired in 1996, he was active as Curator Emeritus at the Transvaal Museum, an Honorary Professor of Zoology at the University of the Witwatersrand, an active Research Associate at the Bernard Price Institute for Palaeontological Research, and Chief Scientific Advisor to the Palaeo-Anthropology Scientific Trust (PAST).
He was an active researcher of fossils of the earliest animals and was co-ordinating a renewed excavation initiative at the Swartkrans Cave.