Hammer (born December 26, 1963) is a United States career diplomat who was the United States Ambassador to Chile.
He was confirmed by the United States Senate on March 6, 2014 and sworn in on March 7, 2014.
He was nominated to be the next ambassador to the Democratic Republic of the Congo by President Donald Trump on June 20, 2018 and confirmed by the Senate on September 6, 2018.