He was born in Woodbury, Connecticut, the son of Timothy and Abigail Jenner Brownson. Brownson graduated from Yale Medical College in 1761, and then established a medical practice in his home town. He was introduced to Liberty County by James Dunwody, a physician, in 1764. He then relocated in Liberty County where he resided at Sunbury, operated a rice plantation, and practiced medicine with Dunwody. Nathan Brownson was a member of the Provincial Congress from 1776 to 1778, after which the Continental Army appointed him head of all Southern military hospitals.
He was elected a state representative in 1781, became speaker of the house, and that same year was elected governor of Georgia. He served as governor until 1782, after which he resumed his position as head of all Southern hospitals. He was a member of the state convention which ratified the U.S. constitution in 1789 and was elected the first president of the state senate.
He owned Saint Catherines Island for a period of time after the Revolutionary War. He was married twice. His second wife , Elizabeth, died in 1775. His son Nathan Brownson Jr. died in 1777. Brownson, his second wife, and his son, are all buried in Midway Church cemetery.
From "Sweet Land of Liberty, A History of Liberty County, Georgia" by Robert Long Groover; Page(s) 211-212; Used by the permission of the Liberty County Commissioners Office