On April 11, 1901, the U.S. Philippine Commission arrived at the Casa Real. Its chairman, William Howard Taft, the future President of the United States, presided over the inauguration of civil government in Iloilo and inducted General Martin T. Delgado as the first provincial governor. The ceremony marked the transition from military to civilian authority under American rule, staged in a building that had served the same purpose for Spain. Six years later, on December 27, 1907, Governor Benito Lopez was assassinated inside the same walls. The Casa Real contained both the pomp and the violence of Philippine political life within a single address. The building was renovated in 1910, but the decades ahead would test it further.

World War II left the Casa Real heavily damaged. A large annex was built after the war to extend its capacity, but on November 4, 1998, that annex was gutted by fire. Meanwhile, the building had become an exercise in institutional overcrowding. After the old Iloilo City Hall was donated to the University of the Philippines Visayas in 1947, the Casa Real was pressed into service as the temporary home of both the city and provincial governments. This arrangement persisted for decades, the two administrations sharing corridors and competing for office space, until the new Iloilo City Hall at Plaza Libertad was completed in 2011. The provincial government itself moved to a new capitol building next door in 2006, leaving the Casa Real to find a new purpose after nearly 140 years of continuous political occupation.

The National Historical Institute formally recognized the Casa Real as a historical landmark in 2010, installing a marker on its walls on April 11, exactly 109 years after Taft's inauguration ceremony in the same building. The location at the junction of General Luna Street and Muelle Loney Street places it in the heart of Iloilo City's heritage district, steps from the waterfront that once made the city one of the busiest ports in the Visayas. In 2022, the National Museum of the Philippines elevated its status further, declaring the Casa Real, along with the adjacent Arroyo Fountain, an Important Cultural Property. The building now mostly serves as a venue for private parties, government functions, and cultural events. Governors still hold their inaugural ceremonies here, maintaining a tradition that stretches back through Delgado and Taft to the Spanish alcalde-mayors who first called these rooms their own.

The Casa Real endures partly because of what it is made of and partly because of what it represents. The original 1869 stone construction has proved remarkably resilient, surviving war damage that destroyed its annex, fire that consumed its additions, and the institutional neglect that often accompanies buildings without a clear tenant. Governor Fajardo's 1873 expansion, with its first-class wood and galvanized iron roof, added a second story that distinguished the building from every other provincial capitol in the archipelago. Standing beside the modern provincial capitol, the Casa Real is both predecessor and counterpoint, its thick walls and low proportions a reminder of an era when permanence was expressed in mass rather than height. The building was restored in 2015, in time for Independence Day celebrations, cleaned and repaired but not reimagined. Its purpose now is remembrance.