According to Wikipedia, Reggie Harding (76ers) was drafted out of high school in 1962. Moses Malone wasn't drafted until 1974, and that was by the ABA Utah Stars.
It was Kobe Bryant.
In 2001 Kwame Brown was drafted out of high school number 1 by the Washington Wizards.
A player can be drafted to the Major Leagues after he completes high school.
It has to be Sebastian Telfair