Thomas Alfred Shannon Jr. is an American diplomat who served as Under Secretary of State for Political Affairs from 2016 to 2018. In early 2017, Shannon served as acting United States secretary of state until President Donald Trump's nominee, Rex Tillerson, was confirmed. He was also acting deputy secretary of state of the United States until the Senate confirmed President Trump's nominee, John J. Sullivan. Born: 1958 In office: January 20, 2017 – February 1, 2017 Wiki link