The State Emergency Service was originally known as the Civil Defence Organisation during World War II. At the end of the war in 1945, the organisation disbanded not to reform until 1961.

The secondment of Mr Ron Nichols to the Police Department as Deputy Commissioner, Civil Defence, was the start of the reformation. The Commissioner of Civil Defence at that time was Lt. Col. G.M. Leane, also the Deputy Commissioner of Police.

It was in 1974 that the name South Australian State Emergency Service (SASES, now known as SESSA) was born. The Commissioner of the SASES (nee Civil Defence Organisation), Lt. Col. G.M. Leane retired and was replaced with a Mr E Aston as the Director. Upon his retirement, the position of Director was changed to a Public Servant position.

The State Emergency Service is an integral aspect of the National Emergency Risk Management Organisation and provides many services with assistance, and provides the Police Commissioner with executive assistance in counter disaster activities.

The operational role of the SES is undertaken solely by volunteers. Permanent officers generally only become involved when requested. They may also co-ordinate emergency/disaster situations, but it is still the volunteer who will carry out the operational tasks.

Currently, the SESSA consists of 65 Units, spread right across the State, with 55 of these situated in the country regions. These Units are then divided into divisions; Riverland, Barossa/Yorke, South East, Murraylands, Mid North, Eyre Peninsula, Metro North, Metro South. There are approximately 6000 registered volunteers in the State Emergency Service of South Australia and about 40,000 across Australia