One day in September 1826, Eliza was chatting with classmates from Rhea Academy when she spotted Andrew Johnson and his family pull into town with all their belongings. They instantly took a liking to each other. Andrew Johnson, aged 18, married Eliza McCardle, aged 16, on May 17, 1827, at the home of the bride's mother in Greeneville. Mordecai Lincoln, a distant relative of Abraham Lincoln, presided over the nuptials.
At 16, Eliza Johnson married at a younger age than any other First Lady. She was rather tall and had hazel eyes, brown hair and a good figure. She was better educated than Johnson, who by this time had barely taught himself to read and spell a little. Johnson credited his wife for teaching him to do arithmetic and to write, as he had never attended school. She tutored him patiently, while he labored in his tailor shop. She often read aloud to him.
The Johnsons had three sons and two daughters, all born in Greeneville:
Martha Johnson (1828–1901). She married David T. Patterson, who after the Civil War served as U.S. Senator from Tennessee. She served as official White House hostess in place of her mother. The Pattersons maintained a farm outside Greeneville.
Charles Johnson (1830–1863) - doctor, pharmacist. At the outbreak of the Civil War, he remained loyal to the Union. While recruiting Tennessee boys for the Union Army, he became the object of an intense Confederate manhunt. He joined the Middle Tennessee Union Infantry as an assistant surgeon; he was thrown from his horse and killed.
Mary Johnson (1832–1883). She married Dan Stover, who served as colonel of the Fourth Tennessee Union Infantry during the Civil War. The Stovers lived on a farm in Carter County, Tennessee. Following the death of her husband in 1864, she married W.R. Brown.
Robert Johnson (1834–1869) - lawyer and politician. He served for a time in the Tennessee state legislature. During the Civil War, he was commissioned colonel of the First Tennessee Union Cavalry. He was private secretary to his father during his tenure as president. He became alcoholic and committed suicide at age 35.
Andrew Johnson, Jr. (1852–1879) - journalist. He founded the weekly Greeneville Intelligencer, but it failed after two years. He died soon thereafter at age 27.