(m. September 16, 1824; died December 19, 1836)
he started practicing law in Nashville and, less than a year after that, had married his first cousin, Emily Tennessee Donelson.
His wife Emily served as White House hostess and unofficial First Lady of the United States due to Rachel Jackson's death in December, 1828. Donelson remained Jackson's private secretary throughout his administration. During his stay in Washington, Donelson had his new home, Poplar Grove (later renamed Tulip Grove), constructed on the land he had inherited from his father, which was adjacent to the Hermitage.
In 1836, Tulip Grove was completed. Shortly afterward Emily died of tuberculosis, leaving four young children. Donelson moved back to Nashville after Jackson's retirement the following year, where he helped Jackson sustain the Democratic party in a variety of ways for the next seven years. These services included writing newspaper editorials defending Democratic principles and helping Democratic candidates campaign for state, local, and national offices. In 1841, Donelson married another cousin, Elizabeth (Martin) Randolph, with whom he would have eight more children. Elizabeth Martin Randolph was a widow of Meriwether Lewis Randolph, a son of Martha Jefferson Randolph, and a grandson of Thomas Jefferson).