Wife of Dr. Thomas Leighton, Martha lived with her husband on the Planet Q. In 2266, a touring acting troupe visited their planet. Her husband believed that the troupe's lead actor, Anton Karidian, was really Kodos the Executioner, the man responsible for a massacre on Tarsus IV that, years ago, left her husband's face scarred.

Martha confided in her husband's friend, Captain James T. Kirk, that she worried about Tom and his obsession with Kodos. Martha became a widow when Tom was murdered by Karidian's daughter, Lenore.