In 1889 he was a member of congress. He was elected as a Democrat to the Fifty-first Congress to fill the vacancy caused by the death of James N. Burnes. He was reelected to the Fifty-second Congress and served from 2 December 1889 to 3 March 1893; chairman, Committee on Pensions (Fifty-second Congress); resumed the practice of law in Platte City, Platte County, Missouri.
Son: Francis M. Wilson, born 1867, died 1932, married Ida Cockrill, born 1873, died 1939. Francis was the United States District Attorney for the Western District of Missouri. He was receiver for the Kansas City Railways Company; Democratic nominee for governor of Missouri in 1928 and 1932, who died a month before the elction of 1932.
Son: Robert Patterson Clark Wilson, II, M.D., born 1876, died 1953, married Helen A. ——, born 1894, died 1958. R. P. C. Wilson, M.D., was superintendent of the Missouri State School for the Feeble-Minded and Epileptic in Marshall, 1912-1920, 1933-1940, and 1949-1953.