American economist and statistician who broadened and helped modernize the character and scope of economics.

Walker was educated at Amherst College and in 1861 enlisted in the Union Army. He was discharged with the rank of brevet brigadier general. In 1869, after having taught for a brief period, he was appointed head of the Bureau of Statistics in the U.S. Department of the Treasury, where he improved the use of statistical techniques. He served as superintendent of the 1870 and 1880 censuses and expanded the coverage of the census to more accurately reflect the development of the United States. He was the commissioner of Indian affairs in 1871, a professor of political economy at Yale University (1873–81), and the president of the Massachusetts Institute of Technology from 1881 until his death. He was also the president of the American Statistical Association (1883–97) and of the American Economic Association (1885–92).

Walker had a decisive influence in discrediting the generally accepted wages (wage and salary)-fund doctrine, which held that the total wage bill was predetermined by the capital set aside for labour. He proposed instead his “residual claimant theory” of wages, which suggested that wage payments were based on what was left after three other costs of production—rent, interest, and profit—had been paid. His theory was never widely accepted. Instead, economists believe that wages reflect worker productivity.

Walker's books include The Wages Question (1876), Money (1878), and Political Economy (1883).