The Yonhap News Agency reported Thursday that Kim was fired by the Central Disciplinary Committee of South Korea's Ministry of Foreign Affairs.
The committee found he had violated the "Kim Young-ran Act" which makes it illegal for public officials to accept gifts, money and goods of certain value, and prohibits "improper solicitations." The act was passed in 2015 as part of South Korea’s efforts to wipe out corruption in the public sector.
Kim reportedly received funding for airline tickets and a hotel stay when he and his family attended the opening ceremony for a golf course in Vietnam last October.
Earlier this year, Kim had been accused of treating embassy officials in an "arrogant and authoritarian manner," a practice called "gapjil" in Korean.
He denied the allegations, Korean newspaper Asia Business Daily reported in April.
Kim’s case was sent to the disciplinary committee, which suggested that some stringent sanction was imminent.
Kim was fired by the panel late last month, but was only recently notified of the decision.
Kim started working for the Korean foreign ministry in 1993, when he was 37. He holds a bachelor's degree in business administration from Seoul National University and a master's degree in history from the University of Cambridge, England.
He worked for five years with Samsung Electronics, being in charge of smartphone sales in Europe. From 1994 to 1997, he taught at the Korean Naval Academy. In 2005 - 2007, he was the first secretary of the Korean Embassy in Russia, and later, the ambassador of South Korea in Ukraine from 2007 to 2010.
He was appointed South Korean ambassador to Vietnam in April last year.