John Joseph Sullivan (born November 20, 1959) is an American lawyer and government official serving as the 19th United States Deputy Secretary of State since 2017.
A member of the Republican Party, Sullivan served as Acting United States Secretary of State from April 1, 2018 to April 26, 2018, following President Donald Trump's dismissal of Secretary of State Rex Tillerson on March 13, 2018, until Tillerson's official successor, Mike Pompeo, was sworn in.
Tillerson did not officially leave office until March 31, 2018.
Sullivan, however, was delegated all responsibilities of the Secretary of State beginning March 13.On October 11, 2019, President Trump nominated Sullivan to be the United States Ambassador to Russia.
On December 12, 2019, the United States Senate confirmed his nomination by a 70–22 vote.