Currently Josette Sheeran holds this position. In this role the Under Secretary assists the U.S. Sherpa, Deputy National Security Advisor David McCormick, who is the principal U.S. official charged with preparing the yearly Summit.
Josette Sheeran currently occupies this position.  In her role, she supports the U.S. Sherpa, Deputy National Security Advisor David McCormick, who serves as the primary U.S. official tasked with overseeing the annual Summit preparations.