After a 35-year government career that spanned the world under six presidents, and even included a brief stint as acting secretary of state, the State Department's top career diplomat has announced his retirement. Though not unexpected, Shannon's retirement is sure to come as a blow to the State Department rank-and-file, particularly among the foreign service who has viewed him as a steady presence during the tumultuous first year of the Trump administration. Shannon joined the Foreign Service in 1984 as a political offer in Guatemala before going on to hold diplomatic posts across Africa and South and Central America. He was the top diplomat for the Western Hemisphere at both the State Department and the National Security Council under President George W. Bush and served as the US ambassador to Brazil before former Secretary of State John Kerry hired him as counselor to the State Department, the first foreign service officer to hold the post in more than 30 years. In February 2016, President Barack Obama nominated Shannon as undersecretary for political affairs, the third-top position at the State Department. After President Donald Trump's inauguration, Shannon served as acting secretary for two weeks before Tillerson was confirmed and then stepped in as his acting deputy for several months until Deputy Secretary John Sullivan arrived at Foggy Bottom. He promised Tillerson he would stay on for a year under his leadership. Shannon agreed to stay on the job until a replacement is identified and confirmed.