Pitcher joined the Army in 1822 as an assistant surgeon, and was promoted to the rank of major in 1836 as a full surgeon. He was president of the Army Medical Board in 1835, and resigned from the Army at the end of 1836.
He moved to Detroit, and was elected mayor for two separate terms, once from 1840–1841 and again in 1843. He was also a regent of the University of Michigan from 1837 until 1852. He served as president of the American Medical Association from 1856–1857, presiding over its annual meeting in Detroit.