The nomination comes after Brown, a Republican, campaigned for Trump in the general election and aggressively lobbied to become secretary of veterans affairs.
Former Fox News host Andrea Tantaros alleged in a lawsuit last August that Brown made several sexually inappropriate comments to her on set: among them, that she "would be fun to go to a nightclub with," which she said was delivered "in a suggestive manner."
He also allegedly crept up behind Tantaros in the cafeteria and touched her lower waist, causing her to pull away and tell him to stop, she said.
Brown, who requires Senate confirmation, did not immediately respond to ABC News’s request for comment. But he has emphatically denied the accusations in the past, tweeting last summer that "as a survivor of sexual abuse, I would never perpetuate language or actions as described in Fox complaint. Actions referenced are fabricated."
In his 2011 autobiography "Against All Odds," Brown wrote that he was abused by a camp counselor as a child.
His nomination comes less than 24 hours after Fox announced it was parting ways with O’Reilly, in the wake of sexual harassment allegations and questions about company culture. The company cut ties with Roger Ailes after he was alleged to have solicited sex from subordinates. Both men have denied the allegations.
In both cases, President Trump has offered words of public support. In July on NBC’s "Meet the Press," he called Ailes "a very, very good person." Sitting in the Oval Office April 5, he told The New York Times, "I don’t think Bill did anything wrong."
After Trump nominated Brown for the ambassadorship, he received congratulations from both sides of the aisle.