The Arizona Republican is among six new resident fellows who will join Harvard's Institute of Politics this fall.
Flake was one of Trump's most vocal GOP adversaries in the Senate before leaving the chamber in December after declining to seek reelection to a second term.
Flake repeatedly called out Trump, accusing him of "reckless, outrageous and undignified behavior" and saying the president's use of the terms "fake news" and "enemy of the people" smacked of Soviet dictator Josef Stalin's propaganda.
Harvard's other incoming fellows include LaTosha Brown, co-founder of the Black Voters Matter Fund; Bob Cohn, president of The Atlantic; and Isabel de Saint Malo de Alvarado, a former Panamanian vice president and foreign minister.
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