The history of the breed goes back to the mid 1800's in Australia. The original breed standard was written by Robert Kaleski in 1902 and approved by the Kennel Club of New South Wales in 1903. The breed was first recognized by the America Kennel Club in 1980.
The Australian Cattle Dog was bred to herd cattle in Australia's inhospitable environment. Everything about the breed today - temperament, coat, physical structure, etc - reflects this original purpose.
Obviously, the breed originated with the ancestral herding collies from England. The breed also finds its blood origins in the Dingo, the Kelpie, and Highland Collie.
For the best historical background on the ACD follow the links below.