Alexander Joy Cartwright III (born 1855) was the son of Alexander Joy Cartwright II, Father of American Baseball.
His father was a Honolulu businessman. On December 27, 1850, King Kamehameha III appointed Cartwright Chief Engineer of the Fire Department of the City of Honolulu. Oahu's Governor, Kekūanāoa, signed the act on February 3, 1851.
The family moved from San Francisco, California in 1849 three years before Alexander's own birth. Mrs. Cartwright and her three children, DeWitt, Mary, and Kathleen, elder sibling of Alexander Cartwright III, traveled to Honolulu from San Francisco in the early 1850s. An elaborate gravestone in the Cartwright cemetery plot in the Oahu Cemetery[1] shows that his sister "Kate Lee" died in Honolulu on November 16, 1851. The other two Cartwright children also died young. Mary Cartwright Maitland died in 1869 at age 24, nearly three years after she married, and had no children. DeWitt died in 1870 at age 26. He was not married and had no children.
Two more children were born to Cartwright and Eliza in Honolulu: Bruce in 1853 and Alexander III in 1855. Alexander III married Theresa Owana Laanui and had two daughters—Daisy Napulahaokalani and Eva Kuwailanimamao. They divorced, and he eventually moved to San Francisco and married Susan Florence McDonald. They had two daughters—Ruth Joy and Mary Muriel. Mary Muriel married Elliott Everett Check. It was through Mary that her grandfather's Gold Rush diary was donated to the Bishop Museum in Honolulu from her estate.
Honolulu had four established baseball clubs popularized by his father. There is recorded evidence that Cartwright's Hawaiian-born sons, Bruce and Alex III, played baseball between the 1860s and 1880s in Honolulu. Without a doubt these young men, standing right beside their father, would not have missed seeing the professional ball players come to town. Yet, no record exists to substantiate this. Given Cartwright's personal connection to the monarchy, it is also feasible that the Cartwright family attended a grand luau held at the queen's home to honor the visitors on Sunday evening. However, no record exists of Cartwright’s attendance at this event either, but he likely attended.[2]