His father was on the provincial council before the Revolution, an active member of the board of proprietors of the colony, and the owner of large landed properties.
During his legislative career, he originated the law that put an end to the local slave trade in 1819, the one that established the school fund, and the provisions of a law that regulated the partition of real estate in New Jersey and the rights of aliens to possess it.
[5] After leaving Congress he resumed his former activities, and was registrar of the board of proprietors of East Jersey.
[6] During the early decades of the 19th century, James Parker held several Black people in slavery in his household.
He was one of the organizers of an association for the purpose of opposing the practice of kidnapping, which was formed in Middlesex County, New Jersey, on July 30, 1818.
[11] Together, they were the parents of:[1] After his first wife's death in 1823, Parker remarried to Catherine Morris Ogden on September 20, 1827.
[5] Through his son Cortlandt, he was the grandfather of James Parker (a major general in the United States Army and a Medal of Honor recipient for his role in the Philippine–American War during 1899),[12][13] Richard Wayne Parker (also a United States Representative from New Jersey).