In 1795, Pierson moved to Ramapo. He practiced law and engaged in mercantile pursuits and manufacturing. He was a Justice of the Peace from 1800 to 1811. He was an associate justice of the Rockland County Court in 1808.
Pierson was elected as a Democratic-Republican to the 17th United States Congress, holding office from December 3, 1821, to March 3, 1823. Afterwards he resumed his former business pursuits. He was largely instrumental in securing the construction of the Erie Railroad.
Pierson was married to Sarah (née Colt) (1772–1820), the daughter of Jabez Colt and Sarah Elizabeth (née Mix) Colt.[3] Together, they were the parents of:[3]
Elizabeth Pierson (1794–1833), who married author and educator Eleazar Lord (1788–1871).
Josiah Gilbert Pierson (1797–1845)
Jeremiah Halsey Pierson (1800–1851)
Theodore Pierson (1803–1816)
Henry Pierson (1807–1807), who died young.
Henry Lewis Pierson (1807–1893)
Benjamin Franklin Pierson (1811–1836)
Pierson died on December 12, 1855, in Ramapo, New York. He was buried at the Ramapo Cemetery.