As the High Performance Director, Marsh will oversee teams of all ages, from South Australia's under-age teams through to the West End Redbacks, as well as the women's State team, the Scorpions.
The former Test star, who has been a consultant to SACA since last year will take over with immediate effect. SACA chief executive Mike Deare said the appointment is a major boost for South Australian cricket.
''Rod is one of the finest cricket minds in the world -- if not the best. We are thrilled that he has accepted our invitation to lead high performance cricket in South Australia,'' he said in a statement here.
''The SACA is keen to see success in the coming seasons, and we believe Rod is the best person to lead our teams to that success,'' he added.
Marsh, known for his tremendous association with Dennis Lillee in the 70's, has spent 10 years as head coach of the Commonwealth Bank Cricket Academy and was the director of the England and Wales Cricket Board National Academy.