She was one of eight children of Captain Robert Kennedy Holliday, a Confederate military officer and quartermaster who served in the 7th Georgia Infantry during the American Civil War, and Mary Anne Fitzgerald, whose family owned Rural Home Plantation.

[1][2][3] She was a cousin of the gambler and gunfighter John Henry "Doc" Holliday and of the landowner and businesswoman Annie Fitzgerald Stephens.

[7] She entered the Sisters of Mercy at the Convent and Academy of St. Vincent de Paul in Savannah, Georgia in 1883, taking the religious name Mary Melanie, after Saint Melania the Younger.

[8] Holliday is believed to be the inspiration behind the character Melanie Hamilton, and possibly Carreen O'Hara, in the novel Gone With the Wind.

[6][8][9] She died at the age of 88 at St. Joseph's Infirmary, and she is buried in the Sisters of Mercy lot in Westview Cemetery.