It was designed by John Smith Murdoch and a team of assistants from the Department of Works and Railways and was intended to be neither temporary nor permanent—only to be a "provisional" building that would serve the needs of Parliament for a maximum of 50 years.

The facade originally incorporated a grid of recessed openings and balconies, with four bays having arched bronze windows and stepped parapets.

Murdoch's simplified classical design is based on a basic square, which provides the building with a regular proportion in terms of fenestration and other elements, including the (now enclosed) verandas and colonnades.

The original roofs were constructed of flat concrete slabs with a membrane waterproofing and finished with a bituminous coating which was designed to be walked on.

On either side of each of the parliamentary chambers are meeting rooms for the government and opposition parties and—at the end of each block—what were intended originally to be suites for the Speaker of the House of Representatives and the President of the Senate.

In the ambulatory are portraits of Australian Governors-General, Prime Ministers, Speakers of the House of Representatives and presidents of the Senate, and pictures of events associated with the building, such as the opening ceremony of 1927.

The chambers of the Senate and House of Representatives are large internal spaces, with ceilings considerably higher than that of King's Hall.

Both chambers are the same size, despite the requirement of section 24 of the Australian Constitution that the House of Representatives should have, as nearly as practicable, twice the number of members as the Senate.

The timber used in the wall panelling, the desks, seats and tables is all Australian black bean wood and Tasmanian blackwood.

Behind it are two thrones, to be used by the monarch and consort or, in their stead, the Governor-General and spouse, at official occasions such as the State Opening of Parliament.

The gallery above the throne was reserved for the press, with others used by the guests of senators, members of the House of Representatives and the general public.

Much of the inspiration (and organisation) for this came from the Usher of the Black Rod and later Clerk of the Senate, Robert Broinowski, and the gardens were designed by Rex Hazlewood.

This shortage of space was compounded by the decision of Prime Minister James Scullin to relocate his principal office from West Block to the building in 1930.

This eventually resulted in all ministers, with their departmental staff, being accommodated in the building over time, compounding the office space problem.

On the Representatives side, larger extensions were required, and a substantial part of the gardens were built over and linked to the main building by a bridge.

The interiors of the 1972–73 extensions reflect fashions of the time, although wooden panelling was used for the walls, in keeping with the older parts of the building, but with an unequivocally 1970s style.

The rooms are now left in the condition they were in at the time they were occupied by Bob Hawke, immediately prior to the move to New Parliament House in May 1988.

In the meantime, John Smith Murdoch, the Commonwealth's chief architect, worked on the design as part of his official duties.

The workers required for the project and their families were housed in camps and settlements and endured Canberra's harsh weather conditions.

Once Parliament commenced sitting in Canberra the transfer of Commonwealth public servants from Melbourne required the construction of suitable housing in the areas of Ainslie, Civic, Forrest (formerly called Blandfordia), Griffith and Kingston.

The building was extensively decorated with many Union Jacks and Australian flags and bunting, with similar schemes used at later events, most notably in 1954 when Queen Elizabeth II visited Canberra for the first time and opened Parliament.

A Wiradjuri elder, Jimmy Clements, was one of only two Aboriginal Australians present, having walked for about a week from Brungle Station (near Tumut) to be at the event.

[6] In early 1973, the rise of global terrorism in Australia – a particular concern of the new Whitlam government – resulted in considerable angst for the security situation at Parliament.

[7] On 11 November 1975, David Smith, Official Secretary to the Governor-General, read a proclamation from the front steps announcing the dissolution of Parliament that followed the dismissal of the Whitlam government by Sir John Kerr; afterwards, Gough Whitlam addressed the crowd and their remarks have become a famous part of Australia's political history.

By the 1970s Old Parliament House had exceeded its capacity and was in need of considerable repair and renovation, especially considering that it was never intended to be a permanent facility and was nearing the end of its useful life.

During the 1920s some, including Walter Burley Griffin, had argued that the building's position would interfere with the vista of a permanent Parliament House.

Griffin had likened the placement of the Old Parliament House to "filling the front yard with outhouses" because the building would interfere with the land axis from Mount Ainslie to Capital Hill.

[9] The building re-opened in 2009 as the Museum of Australian Democracy at Old Parliament House, an executive agency of the Department of the Prime Minister and Cabinet.

The building was set alight twice during protests staged by so-called sovereign citizens, a movement that rejects elected officials and law enforcement, including the courts.

Ngunnawal elder Matilda House-Williams, who was present when the site was established in 1972, condemned the fire and said the protest did not represent the embassy or the Indigenous people of Canberra.