Hudson was born of US parents living in Argentina. He spent his youth studying the local flora and fauna and observing both natural and human dramas on what was then a lawless frontier. He settled in England in 1869. He produced a series of ornithological studies, including Argentine Ornithology (1888-1899) and British Birds (1895), and later achieved fame with his books on the English countryside, including Hampshire Days (1903) and Afoot in England (1909), which helped foster the back-to-nature movement of the 1920s and 1930s.
He is best known for the exotic romance Green Mansions (1904).
Other works include