He also held office as minister of Economy and Finance from 2005 to 2006, ambassador to the United States from 2009 to 2012, and as chairman of the Korea International Trade Association from 2012 to 2015.

[3][4] On 27 December 2024, Han was impeached by the National Assembly of South Korea due to his refusals to promulgate two special counsel bills that sought to investigate the impeached president Yoon Suk Yeol and his wife Kim Keon-hee or to appoint three National Assembly-designated candidates for the Constitutional Court of Korea.

[7] Han started his political career at the National Tax Service in 1970 and joined the Economic Planning Board four years later.

[12] As Han was viewed as a political centrist, President Lee Myung-bak appointed him as South Korean ambassador to the United States in 2009.

[5][17] In February 2024, after a government plan to boost admissions into medical schools was introduced, thousands of doctors resigned in protest, claiming it would hurt the quality of service.

Han ordered emergency measures to combat the crisis, such as the use of telemedicine, more public hospital operations, and the opening of military clinics.

[20][21] A couple days later, Han announced that South Korea would send military and community doctors to combat the ongoing emergency.

[24] In the same month, amid the prolonged medical crisis, Han announced that hospitals could extend the application period for trainee doctor programs.

Among the bills vetoed were proposed amendments to the Grain Management Act, which would have required the government to purchase surplus rice to stabilize prices during market fluctuations.

Other measures he vetoed included a bill requiring companies to submit requested data to members of the National Assembly, saying that it was an invasion of constitutional rights to privacy.

[35] On 24 December, the Democratic Party said that it would seek to impeach Han due to his failure to promulgate two special counsel bills that sought to investigate Yoon and his wife Kim over his martial law declaration and charges of corruption.