Highway 1 was created as part of the National Route Numbering system, adopted in 1955.[1] The route was compiled from an existing network of state and local roads and tracks.[1] Highway 1 is the only route to reach across all Australian states, plus the Northern Territory. Many of the other national routes are tributaries of Highway 1.

Under the original Highway 1 scheme, certain major traffic routes that ran parallel to the main route were designated National Route Alternative 1. Most of these route designations have been replaced by either a state route designation, or an alpha-numeric route designation, depending on which state the section is in. An example of the Alternative 1 designation remaining is on the old Princes Highway route from Dandenong to South Melbourne in Victoria.

The entirety of Highway 1 was originally marked with a National Route 1 shield (black number on a white shield). In 1974, the segments of the route that were declared part of the National Highway network were updated to use the National Highway shield (gold number on a green shield).[2]

Since that time, all states and territories except for Western Australia have adopted (or are in the process of adopting) alphanumeric route numbers. As a consequence, much of Highway 1 is now marked with a M1, A1 or B1 route marker (depending on the route's quality and importance). A notable exception is in Tasmania, which was the first state to adopt alphanumeric route numbers but Highway 1 is still marked with a National Highway 1 shield.

In South Australia, sections of Highway 1 which were once part of the National Highway were marked as "National Highway A1" or "National Highway M1" but have since been replaced by the standard "A1" and "M1" shield markers