Brisbane's evolution throughout the 20th century is a captivating narrative of social, political, and architectural milestones that shaped the city into the vibrant hub it is today. The century began with the federation of Australia in 1901, celebrated in Brisbane with a grand arch on Queen Street and the foundation stone of St John's Cathedral laid by the Duke of Cornwall and York. The establishment of the University of Queensland in 1909 marked a significant educational advancement, beginning its journey at Old Government House before moving to Fernberg House in 1910.

Tensions simmered in the early 1910s as labor unrest ignited the 1912 Brisbane General Strike, also known as Black Friday, following tramway employees' suspension for displaying union badges. This strike highlighted the growing labor movement and culminated in police brutality against trade unionists. In a stark contrast to this local unrest, between 1911 and 1914, Brisbane welcomed a wave of Russian immigrants fleeing political turmoil and persecution, notably many Jewish refugees escaping pogroms.

The aftermath of World War I saw increasing conflict between returned soldiers and perceived disloyal socialists, culminating in the violent Red Flag riots from 1918 to 1919. The pinnacle of these clashes was the Battle of Merivale Street, where a crowd of ex-servicemen clashed with police over tensions surrounding the Russian community.

The 1920s brought significant administrative changes, with numerous municipalities amalgamating to form the City of Brisbane, leading to a more centralized governance under the Brisbane City Council. This decade also saw the completion of Brisbane City Hall and the Shrine of Remembrance in ANZAC Square in 1930, solidifying the city’s commitment to memorializing its wartime sacrifices.

As Brisbane navigated through the tumult of the 1930s and 1940s, including the Pineapple Rebellion in 1939, the city became a critical Allied military base during World War II. The city’s strategic location saw it serve as the headquarters for General MacArthur, with over a million U.S. troops passing through during the war. However, this period was marred by racial tensions, exemplified in the infamous Battle of Brisbane in 1942, where American and Australian servicemen clashed.

Post-war Brisbane grappled with its identity, shedding the stigma of a “big country town.” The late 1950s and 1960s saw cultural shifts, with a burgeoning counterculture emerging from the University of Queensland, while simultaneously dealing with a political climate characterized by police corruption and social conservatism under the leadership of Joh Bjelke-Petersen.

The late 1970s witnessed significant civil liberties battles, with the government enacting a statewide ban on protests, leading to widespread defiance and the innovative Phantom Civil Liberties Marches. Bjelke-Petersen's tenure ended amidst the Fitzgerald Inquiry, which revealed extensive police corruption, ultimately reshaping the political landscape in Queensland.

The 1980s marked a new era of development and modernization for Brisbane, highlighted by the successful hosting of the Commonwealth Games in 1982 and World Expo 88, both of which ushered in an unprecedented scale of public expenditure and infrastructure development. Despite facing challenges such as urban decay, the city embarked on extensive urban renewal projects, revitalizing its inner city and paving the way for Brisbane to emerge as a thriving metropolitan destination.

Brisbane's 20th-century journey is a testament to its resilience and adaptability, setting the stage for the dynamic city it continues to become.