What roles did Americans play in the expanding global empires of the nineteenth century? Thomas M. Larkin examines the Hong Kong–based Augustine Heard & Company, the most prominent American trading firm in treaty-port China, to explore the ways American elites at once made and were made by British colonial society. Following the Heard brothers throughout their firm's rise and decline, The China Firm reveals how nineteenth-century China's American elite adapted to colonial culture, helped entrench social and racial hierarchies, and exploited the British imperial project for their own profit as they became increasingly invested in its political affairs and commercial networks. Through the central narrative of Augustine Heard & Co., Larkin disentangles the ties that bound the United States to China and the British Empire in the nineteenth century. Drawing on a vast range of archival material from Hong Kong, China, Boston, and London, he weaves the local and the global together to trace how Americans gained acceptance into and contributed to the making of colonial societies and world-spanning empires. Uncovering the transimperial lives of these American traders and the complex ways extraimperial communities interacted with British colonialism, The China Firm makes a vital contribution to global histories of nineteenth-century Asia and provides an alternative narrative of British empire.