Kay Gray was developed by the Wisconsin grape breeder Elmer Swenson circa 1980 and is named after a family friend. It is a seedling of Swenson's own ES 217 (a cross of MN 78 and Golden Muscat). Swenson collected open-pollinated seeds from this vine, and one seedling eventually became Kay Gray. Because of this, the male parent is unknown, though Swenson suspected it might be a nearby vine of Onaka, an old South Dakota cultivar.