The 20-year-old clinched the top accolade ahead of last year's winner, cricketer Hashim Amla, swimmers Natalie du Toit and Cameron van der Burgh, athletes Caster Semenya and Oscar Pistorius, Bafana Bafana striker Siyabonga Nomvete and Protea wicket-taker Vernon Philander in Johannesburg on Sunday night.
Le Clos became an overnight sensation when he beat Michael Phelps by a whisker for the gold medal in the 200m butterfly at the 2012 London Olympics. He went on to win silver in the 100m butterfly behind Phelps.
Philander claimed the sportsman of the year trophy following a prolific debut Test season where he became the second-fastest man to take 50 wickets in the history of cricket.
Rowing South Africa were also big winners on the evening, scooping three awards with their president Wimpie du Plessis named administrator of the year and the sporting code taking the federation of the year award.
The Olympic gold-medal winning South African men's coxless lightweight fours rowing team of Sizwe Ndlovu, Matthew Britain, John Smith and James Thompson walked away with the team of the year award.
Semenya, who was the country's only medallist in the track and field at the London Olympic Games, clinching the 800m silver medal, received the sportswoman of the year award.
In the coach of the year category, Banyana Banyana's Joseph Mkhonza walked away with the spoils. Mkhonza led the South African women's soccer team to its first Olympic Games where they failed to advance past the group stages at the London showpiece.
Legendary Paralympian Du Toit was honoured during the evening by being named sportswoman of the year with disability. She bowed out from competitive swimming after this year's Paralympic Games having won a total of 13 gold and two silver medals in Paralympic competitions.
The sportsman of the year with disability went to Pistorius, who this year made history by competing at both the Olympics and Paralympics. – Sapa
- Sports star of the year: Chad le Clos (swimming).
- Sportsman of the year: Vernon Philander (cricket).
- Sportswoman of the year: Caster Semenya (athletics).
- Coach of the year: Joseph Mkhonza (football).
- Sportswoman of the year with Disability: Natalie du Toit (swimming).
- Sportsman of the year with Disability: Oscar Pistorius (athletics).
- Federation of the year: Rowing.Team of the year: Rowing.
- Administrator of the year: Wimpie du Plessis (rowing).
- Newcomer of the year: Siya Kolisi (rugby).
- Volunteer of the year: Sondiso Magajana (judo).
- School team of the year: Ithembelihle High (rugby).
- Journalist of the year: Velile Mbuli
- Photographer of the year: Sydney Seshibedi
- Recreation body of the year: Vakhegula (Vakhegula football)
- Steve Tshwete Lifetime Award 2012: Elijah Tap Tap Makhithini (boxing), Papwa Sewgolum Sewsunker (golf), Sam Ramsamy, Petros Molemela (football), Sally Little (golf), Joost van der Westhuizen (rugby).
- Green Jacket recipients for 2012: Matthews Motshwareteu (athletics), Blanche Moila (athletics), Grant Khomo Was bestowed with order of Ikhamanga (cricket, rugby, football and tennis), Nelson Teenage Dladla (football).