The council initially held their meetings in a room adjacent to the old Government House that was located near to the present site of Franklin Square. Parliament House was originally designed as the Customs House in colonial Georgian architecture style by skilled convict architect John Lee Archer in 1830. The site for the building had originally been a market, but had been converted into timber yards in the 1820s. The site was reserved in 1832 for the building of a customs house due to its close location to the wharves of Sullivans Cove (the building was originally closer to the water's edge than it is today following further reclamation).
Before reclamation of the grounds began in 1832 the site was close to the water so it was an obvious location for the customs operations. (One of the prints in the Parliamentary Museum gives a clear illustration of how close the building was to the water.) Between 1832 and 1840 golden honey colored sandstone was quarried from locations in the Queens Domain and Salamanca Place (now the site of Salamanca Square), and a small railway was constructed to ferry the blocks to the construction site.
Construction began in on 5 January 1835, and using mostly convict labour, the basement level had been completed by March 1836. By 1838 the second story had been added and the building was ready for staff of the Customs Department to move into on 1 September 1840. By 1841 the building was fully operational as the colony's customs house. At that time, the Legislative Council, which had been formed in 1825, was meeting in a room adjacent to the old Government House, but the location was less than adequate for such meetings. It was proposed that the meetings should be held in the spacious new 'Long Room' of the Customs House, and 19 June 1841, the first Legislative Council meeting was held within the building.
In 1845 the original markets upon the reclaimed land were removed and replaced by timber yards. (Ironically, adjacent to this area is now the site of Tasmania's most significant and popular market, the weekly Salamanca Market.). In 1850 the British Parliament enacted the Australian Colonies Government Act, which gave Van Diemen's Land the right to elect its first representative government. The size of the Legislative Council was increased from six to 24. Eight members were appointed by the Governor, and 16 were elected by property owners. The new Legislative Council met for the first time in 1852, and by 1854 they had passed the Tasmanian Constitution Act, granting Van Diemen's Land responsible self-government and a new parliament.
In 1855 Queen Victoria granted Royal Assent and Van Diemen's Land became a self-governing British Colony. The following year, 1856, one of the new parliament's first acts was to change the name of the colony from Van Diemen's Land to Tasmania. In April 1856 renovations began to the Customs House to allow it to accommodate the new parliament, and on 2 December 1856 the first sessions of parliament were held, with the new House of Assembly sitting in the Long Room, and the Legislative Council moved to their new chamber at the opposite end of the building.
The Customs Department finally moved out of the building altogether in 1904, moving to a new location in Davey Street next to the Tasmanian Museum and Art Gallery, leaving the building be solely occupied by the Parliament of Tasmania. Between 1938 and 1940 Parliament House was again renovated to construct a new chamber for the House of Assembly, and convert the Long Room, where they had been meeting for the previous 82 years, into a Member's Lounge.
The new House of Assembly Chamber was formally opened on 14 May 1940, whilst Tasmania was involved in Australia's World War II commitments. In December 1940 extensions were also added to the Legislative Council Chamber to create the Murray Street wing. Further alterations were made to the building beginning in 1977. Member's offices, a Hansard office, Parliamentary Library and Museum, committee rooms, a dining room, reception area, interview rooms and other additional facilities were added, and a formal re-opening was held on 16 April 1980. The most recent alterations began in 1998 and are currently still underway and are in the form of conservation work, and restoration of sections of the building to try and revert it to its original character.
Parliament House is one of the clearest examples of how Archer designed his work to have a sense of strength and permanence. Whilst significant renovations to the interior have taken place, and the slate roof was removed and replaced with tiles, the façade still remains today almost exactly how it was first constructed. Unlike a lot of Archer's penal projects, which have since been demolished, Parliament House is still occupied today by the Parliament of Tasmania. For this reason alone it is one of, if not the most significant project of Archer's entire career.