For additional meanings of "McPherson", please see McPherson.
McPherson was a genetically-engineered "superman" (termed an "Augment") from Earth's 20th century, a follower of Khan Noonien Singh and survivor of the Eugenics Wars. McPherson escaped Earth aboard the SS Botany Bay. In 2267, the Botany Bay was discovered by the USS Enterprise, where he was among the 72 surviving members of Khan's original group of 84. (TOS: "Space Seed")