Nehemiah Marks was born in Derby, Connecticut, on 9 October 1746. He was the son of Mordecai Marks (1706-1771), a Sephardic Jew who emigrated from London, England, in 1721 and became a prosperous merchant. He converted to the Anglican faith and in 1729 married Elizabeth [Hawkins] of Derby, Connecticut. Soon after the Revolution began, Nehemiah Marks went to New York where it is believed he carried despatches for the British army. He served as a captain in the Armed Boatmen, a Loyalist corps, with a commission dated 5 October 1782. His commission as a lieutenant in the Maryland Loyalists, dated 1 October 1783, can be found among the papers of his son, Nehemiah Marks, Jr. With the evacuation of New York City, Nehemiah Marks, Sr. was forced to seek refuge in Nova Scotia, and on 1 November 1783, he was appointed a captain in the Nova Scotia Militia for the District of Port Mouton, and charged with the responsibility of settling his men and their families. The refugees remained at Port Mouton for the winter of 1783, but in 1784 Captain Marks decided to move to the Falls of the St. Croix River (St. Stephen, New Brunswick), and a number of his men chose to accompany him. On May 23, 1784, a group of about 200 including men, women and children led by Capt. Nehemiah Marks, steered up the St. Croix River to the head of tide and landed on the Canadian banks of the St. Croix River.
For their loyalty, King George III granted them land, which over time they made prosperous. A large community grew around shipbuilding and lumbering industries, which would eventually become the Town of St. Stephen.
In 1770, Nehemiah Marks married Betsy (Elizabeth) Hawkins (1751-1812), the daughter of Abraham Hawkins (b.1725) and his wife, Elizabeth Basset (b.1728) of Derby, Connecticut. Eight of their children are known to have survived, including: Elizabeth Ann (b.1772), Betsy (b.1774), Hannah (b.1776), George Beckwith (b.1778), John, Nehemiah (1794-1853), Rebecca, and Abraham Hawkins (b.1796). When Nehemiah Marks died in 1799 at the age of fifty-two years, he left an estate that included a house and a store in St. Stephen, a large tract of land on which much of the present Town of St. Stephen is built, and several hundred acres of woodland.

Nehemiah Marks was the son of the Loyalist, Nehemiah Marks, Sr. (1746-1799) and his wife Betsy (Elizabeth) Hawkins (1751-1812). They were Loyalists who settled at the Falls of the St. Croix River (St. Stephen, New Brunswick) in 1784, and are considered prominent figures in the early development of St. Stephen. Nehemiah Marks was born in 1794, and by the time of his marriage in 1812 to Sarah Thompson, the daughter of James Thompson of St. Stephen, he was largely responsible for his father's business interests which consisted of the family store, farm, and wood lands. During the next three decades he expanded his timber holdings in New Brunswick and in Maine, and supplied cargoes of lumber for vessels sailing to England and to the West Indies. Beginning in the 1820s, he started to acquire vessels which he owned and operated himself, and which carried his lumber to many ports. Eventually, he acquired a fleet of nine brigs, one barque, and two schooners, including the brig "Nehemiah Marks" which was built at his own wharf in St. Stephen. In addition to the vessels he owned outright, he was part owner of other ships which he did not manage. Using a network of agents in ports in the West Indies, Ireland, United States, and Liverpool, England, his ships and their cargoes were sent to many ports, according to the season and the market conditions. Returning vessels usually brought clothing, furniture, dry goods, salt, coal, rum, and many other goods for sale in the store. As horses and horse racing were a life-long passion, on occasion, a race horse was included in the cargo. He was also an officer in the Charlotte County Militia for more than twenty years.
When Nehemiah Marks died on 17 August 1853, all of the ships in his fleet had been sold or lost by shipwreck, but his estate still included timber and farm land in Charlotte County, town property in St. Stephen, and vast holdings of wood land in Maine and in York County, New Brunswick. For over twenty years, Nehemiah Marks was an officer in the Charlotte County Militia and Lieutenant Colonel of the Fourth Battalion. He was Overseer of the Poor for St. Stephen Parish for at least ten years, and was an active member of Christ Church (Anglican) in St. Stephen. He was survived by six children: John, Joseph P., Abraham H., Nehemiah, Elizabeth Caroline, and Sarah Henrietta.