Walter Palmer entered his Bloomington, Minnesota, dental practice without a word amid a crowd of protesters and reporters, according to the Minneapolis Star Tribune newspaper.
A photo tweeted by broadcaster CBS meanwhile showed the 55-year-old, casually dressed in a dark polo shirt, surrounded by people scrambling to take pictures on their cell phones.
Zimbabwe has asked the United States to extradite Palmer to face charges over the July hunt.
In his first interview since the uproar, Palmer told the newspaper over the weekend that he and the others in his party had no clue that the animal they were hunting was the revered feline that has been a well-known attraction at the Hwange National Park.
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He also maintained he thought that the hunt, during which he was armed with a powerful crossbow, was legal.
Palmer declined to say whether he would abide by any request to return to Zimbabwe over legal allegations, and an attorney present for the interview added that there had been "no official allegations that he's done anything wrong."
In other comments, Palmer said the ordeal had been particularly difficult for his wife and daughter, who had been threatened on social media.