But recently, it’s his facial hair that has left South Koreans bristling.
To some South Koreans, it evokes memories of Japanese colonial rule over the country from 1910 until 1945.
Those who feel affronted say his facial hair is reminiscent of the moustaches worn by Japan’s governor-generals in that era.
Mr Harris, the son of a US Navy officer and a Japanese mother, has previously raised tensions by demanding that South Korea pay more for hosting US troops.
But speaking to reporters on Thursday, he suggested the criticism stemmed from his heritage.
“My moustache, for some reason, has become a point of some fascination here,” Mr Harris said. “I have been criticised in the media here, especially in social media, because of my ethnic background, because I am a Japanese-American.”
Why the controversy over a moustache?
Mr Harris, 63, has been US ambassador at a time of heightened tensions between South Korea and Japan.
Those tensions were inflamed in November 2018, when South Korean court rulings ordered Japanese firms to pay compensation to Koreans over forced labour during World War Two.