Joseph Dwight was born in 1702, in Hatfield, Massachusetts, the son of Henry Dwight and Lydia Hawley. He graduated from Harvard in 1722 and worked as a merchant until 1731, at which point he began pursuing a career in law. After his admission to the Massachusetts Bar Association in 1733, he moved to Brookfield, Massachusetts. The Worcester County Common Court of Pleas appointed him a judge in 1739, and he went on to become an eleven-times member of the Massachusetts Colonial Council from 1731-1751. Upon the outbreak of King George's War (1744-1748), Dwight, then a colonel, took command of a group of local Massachusetts militiamen. He rose to the rank of brigadier general (1745) commanding the Massachusetts Artillery, making him second in general command of all forces on a proposed Canadian Expedition.
He led his troops to the western frontier in preparation for a British push into Canada that was supposed to end French incursions on British territory. Dwight was present at the Siege of Louisbourg, arguably the largest military engagement and Britain's greatest victory during King George's War. General William Pepperrell applauded him for his bravery and comportment during the taking of the French fort. The 1748 Treaty of Aix-la-Chapelle officially ended the war in North America. After the conclusion of the war, Dwight served as speaker for the Massachusetts Colonial Council (1748-1749). During the French and Indian War, he commanded a brigade of militia at Lake Champlain in 1756, and served as chief judge of Berkshire County upon its formation in 1761. He died at Great Barrington, Massachusetts, on June 9, 1765.
In 1726, Dwight married Mary Pynchon, with whom he had nine children: Mary (1727-1734), Dorathy (b. 1729), Lydia (b. 1732), Henry (1733-1756), Mary (b. 1736), Bathsheba (1738-1761), Elijah (b. 1740), Moses (1742-1764), and Joseph (b. 1745). After Mary’s death in 1751, he married Abigail Sergeant, daughter of Colonel Ephraim Williams, in 1752. Dwight and Abigail had two children: Pamelia (b. 1753) and Henry (b. 1757).