A postal service operated in Moreton Bay from convict times. After free settlement, various part-time post masters distributed mail from premises in Queen Street. The first full-time Post Master, John Barney, was appointed in 1852. When he died in 1855, his wife Elsie succeeded to the position and she managed the distribution of mail to a growing population which by 1859 numbered 30 000.
By 1863, the new Post Master General Thomas Murray-Prior regarded the Queen Street site as inadequate. He nominated the present site, then containing the former Female Factory, as the most appropriate location for a new General Post Office. Plans were prepared by the Colonial Architect Charles Tiffin, but a severe financial crisis in 1866 halted any further progress. In 1871 tenders were called on a new design prepared by Tiffin's successor FDG Stanley and the contract was awarded to John Petrie. Petrie drew on local materials and expertise in the erection of the new building, using porphyry (probably from Kangaroo Point), sandstone from Murphy's Creek and Breakfast Creek and iron from Smellie & Co for the upper floor colunms and railings. By the end of September 1872, the building was complete - at a cost of £7450. A clock for the pediment was to come from England and some interior fittings were to be finished. Stanley's design, like Tiffin's earlier one, made provision for large shaded outside areas to accommodate the hundreds of clients who had to wait for their mail.
Another communication service, the telegraph, had been in existence in Queensland since 1861 when Brisbane was linked with Ipswich, the Darling Downs and with New South Wales via Annidale. Thereafter telegraph lines were erected throughout the colony – by 1872 Brisbane was linked with the Gulf of Carpentaria. The growth of telegraph services strained accommodation at the first Telegraph Office in an old church in William Street and by the late 1870s a decision was made to relocate the Telegraph Office to the GPO site. By 1877 plans for a twin to the GPO were drawn up and, once again, John Petrie's tender was successful. Construction of the new Telegraph Wing proceeded and by November 1879 the new building was complete. The two wings were linked by an arcade and a tower - the latter was never finished. A two-storeyed building behind the Telegraph Wing, facing Elizabeth Street was built in the same year.
Rapidly developing technology and an expanding Queensland population created accommodation pressure on the site and by the time the Telegraph Wing was completed, extensions had already been constructed on the GPO wing. In late 1880 the government assumed responsibility for another communication service, the telephone. The first telephone exchange was installed in the Telegraph Wing. By 1889, the exchange occupied a new floor on top of the 1879 Elizabeth Street building.
Accommodation continued to prove inadequate and, despite piecemeal extensions, by the 1890s there were calls for an entirely new building on the whole site. Early in 1900 a design competition was announced, attracting entries from architects throughout the colonies. With Federation however, Post & Telegraph affairs became the responsibility of the Commonwealth Government and although designs for a new building were sent to Head Office in Melbourne, the plan lapsed.
In 1908, plans were made to rationalise space on the site which had become cluttered with buildings. On the Post Office side a large extension was erected behind the GPO and a new brick building with basement and three floors, designed by Thomas Pye, was constructed facing Elizabeth Street. A two-storeyed building was erected behind the Telegraph Wing and the whole complex was fitted with an electrical system, including an electric lift .
Since 1911 various extensions have been erected above and between existing buildings. In 1927 the southern colonnade and stairs of the Telegraph Wing were demolished. In the 1930s there was another call for a new building but plans were delayed and then lapsed. The 1970s saw a $700 000 restoration program including the installation of a new clock in the Post Office pediment and the opening of a Post and Technology Museum in the Telegraph Wing. The interior of the GPO was remodelled in 1989.