James was the first son of Joseph Bernard Simpson & Mary Ann Montgomery. He was born near Port Tobacco, Maryland, in 1783. He was married to Mary Alice Boone, daughter of John and Frances, on 12 June 1807 by Fr. S. Theodore Badin, OB, at St. Rose Catholic Church in Washington County, Kentucky. They had 5 children: Celestine Sylvester (b. 1808), Mary Mathilda (b. 1809), Rose A. (b. 1810), Ursula (b. 1813, and Mary Ann (b. 1815). During his time in Kentucky, James embarked on a career as a schoolteacher. Mary died in 1815 and James remarried on 4 November, 1816 to Monica McAtee, daughter of Henry McAtee, one of the original landowners in Washington County, Kentucky. The marriage was officiated by Fr. S. L. Montgomery, OB, at St. Rose.
Sometime around 1819, James and his family moved west to the town of Litchfield (Leitchfield), in Grayson County. James and Monica had six children while living in Grayson County: Henry Dionysius (b. 1819), James D. (b. 1821), Edmond A. (b. 1823), Margaret Ann (b. 1824), Thomas Aquinas (b. 1828) and John Chrysostom (b. 1828). Due to fires in 1864 and 1896, some of the valuable records of Grayson County were destroyed.
In 1828, the Simpson family moved to the Sugar Creek community of Sangamon County, Illinois, about 15 miles northwest of Springfield, in what is now the Lincoln New Salem State Park. Soon after, Monica had two more children: Teresa (b. 1830) and Alfred Linus (b. 1831).
James moved his family to Randolph County, Illinois, in 1838. The following year, he purchased 40 acres of land from the United States government at 12 ½ cents per acre. The original Simpson land grant (signed by President Martin Van Buren), near the old town of Marigold, still remains in the Simpson family 170 years later.
James Montgomery died in 1846 and his will, probated the same year, bequeathed equal shares of his estate to all of his children, even the daughters--a very unusual act for that period of time. Henry D. and James D. were appointed the executors of the will. Monica lived on a small section of the family farm until she died in 1867. Both James and Monica are buried in St. Patrick Catholic Cemetery in Ruma, Illinois.
He was a schoolmaster, carpenter, & farmer.