Iaukea married Charlotte Kahaloipua Hanks (1856–1936) on April 7, 1877. They had met through the acquaintanceship of Charlotte's aunt Uwini Auld and Queen Emma. The only daughter of American businessman Frederick Leslie Hanks and Chinese-Hawaiian Akini, Charlotte was of mixed-Caucasian, Native Hawaiian and Chinese descent. Her father was allegedly a relative of Nancy Hanks, the mother of President Abraham Lincoln, and had settled in Hawaii after his second visit in 1853. A descendant of the Kahaloipua line of chiefs, her genealogy was considered of a higher rank than her husband. Her maternal grandfather was the early Chinese businessman Tyhune (i.e. Wong Tai-hoon), who owned the Tyhune Store in downtown Honolulu from the 1830s to the 1850s and invested in sugar, shipping, merchandise, and liquor sales. She inherited lands in Waikiki and Honolulu from her maternal grandmother Wahinekapu, a Hawaiian chiefess and the daughter or sister of Kahanaumaikai, who had been a recipient of land in the Great Māhele. Charlotte served as a lady-in-waiting for Queen Kapiʻolani, and was a close friend of Liliʻuokalani. During the monarchy, she received the honor of Knight Companion of the Royal Order of Kapiolani.