The exact age of the skeleton remains a mystery, but it is believed to be around 3.67 million years old.
The bones were discovered in the Sterkfontein caves outside Johannesburg after foot and leg bone fragments were found from rock blasted from the cave by miners.
"What Little Foot shows us is that the image represented in our books of our ancestors walking on all fours and then rising gradually is totally false", he said.
The Associated Press reports The University of the Witwatersrand revealed the almost-complete Australopithecus fossil on Wednesday.
It is, by far, the most complete hominin skeleton globally older than 1.5 million years, and the oldest hominin skeleton ever found in South Africa.
South Africa's "Cradle of Humanity", a large piece of land made up of hills and plains outside of Johannesburg, was the site of many ancestral discoveries - including this most recent unveiling of the hominid nicknamed "Little Foot".
Little Foot is relatively small, with a height of about 4 feet 4 inches.
It's expected that Little Foot will be able to provide a wealth of information about our early Australopithecus ancestors - how they moved, how their skeletons are put together, what they looked like. The face, teeth, and pelvic structure of the fossil indicate that Little Foot is a young girl.
We can say for example that the legs are longer than the arms, that is to say, the proportions more similar to ours and not like those of monkeys.
Though now on display, scientists will continue to study Little Foot's anatomy to ascertain her place on the hominid family tree - and to shed further light on the story of early human evolution.
Professor Clarke, from the Evolutionary Studies Institute at the University of Witwatersrand, Johannesburg, said: "This is one of the most remarkable fossil discoveries made in the history of human origins research and it is a privilege to unveil a finding of this importance today".
Prof. Ron Clarke with his assistants discovered the fossils at the location, for which they spent a couple of decades to clean, excavate, reconstruct and analyze the skeleton. "It was like excavating a fluffy pastry out of concrete", Prof Clarke said.
"The process required extremely careful excavation in the dark environment of the cave".
Radio 702's Azania Mosaka spoke to Professor Robert Blumenschine, the chief scientist at the Palaeontological Scientific Trust, about Little Foot. "Not only is Africa the storehouse of the ancient fossil heritage for people the world over, it was also the wellspring of everything that makes us human, including our technological prowess, our artistic ability, and our supreme intellect", he says.