The development of Canberra throughout the 20th century marked a period of transformation from a fledgling provisional capital to a fully functioning national city. In 1913, the Commonwealth government purchased the pastoral property of Yarralumla to serve as the official residence of the Governor-General of Australia. Renovations to expand and modernize the estate began in 1925, and by 1927, the property was officially designated Government House. That same year, the Provisional Parliament House opened on 9 May, marking the formal relocation of the Commonwealth Parliament to Canberra, while Prime Minister Stanley Bruce took residence in The Lodge.

Early city development faced significant challenges, with the Great Depression of the 1930s and World War II slowing progress. Several planned projects, including major cathedrals for the Roman Catholic and Anglican communities, were delayed or never completed, although the Roman Catholic parish church of St Christopher in Manuka was later remodeled into a cathedral in 1973, becoming Canberra’s only cathedral.

From 1920 to 1957, advisory bodies such as the Federal Capital Advisory Committee, the Federal Capital Commission, and the National Capital Planning and Development Committee oversaw expansion plans in the absence of city founder Walter Burley Griffin. However, their lack of executive power and the tendency for decisions to bypass their guidance caused inefficiency and slowed cohesive development.

Despite these challenges, Canberra hosted notable national and international events. In January 1939, the 24th Meeting of ANZAAS brought 1,250 delegates to the city, including the renowned writer H. G. Wells, who toured bushfire-threatened areas with Governor-General Lord Gowrie. The event coincided with a severe heatwave and the catastrophic Black Friday bushfires in Victoria, underscoring the growing prominence of the young capital on the national stage.

Post-war Canberra faced criticism for its scattered layout and underdeveloped infrastructure. Prime Minister Sir Robert Menzies initially considered the capital an embarrassment, describing it as “several suburbs in search of a city.” Over time, Menzies became a strong advocate for Canberra’s development, accelerating population growth, relocating government departments from Melbourne, and implementing housing projects to accommodate the expanding workforce. Between 1955 and 1975, the population grew by more than 50 per cent every five years, reflecting the city’s rapid expansion.

The National Capital Development Commission (NCDC), formed in 1957, was granted executive powers that ended decades of disputes over urban planning. One of its most significant achievements was the completion of Lake Burley Griffin in 1964, four years after construction began. The lake, a central feature of Griffin’s original city design, enabled the development of the Parliamentary Triangle and established Canberra’s iconic urban landscape. Since then, a variety of national institutions and important buildings have been constructed along its shores, solidifying Canberra’s status as Australia’s political, cultural, and administrative center.

Canberra’s 20th-century growth reflects a trajectory from a sparsely populated provisional capital to a planned, vibrant national hub, integrating the vision of its founders with the practical needs of a modern government city.