The incident, which reportedly occurred on Monday afternoon, involved a National Park Services employee while the dog was out on the White House's South Lawn.
According to the network, the member of staff was working at the time and had to leave their role to get the bite checked out by the White House medical unit.
Michael LaRosa, First Lady Jill Biden's press secretary, confirmed the incident when contacted by CNN for a comment.
"Yes, Major nipped someone on a walk. Out of an abundance of caution, the individual was seen by WHMU and then returned to work without injury," Mr LaRosa said, adding that the three-year-old German shepherd was still "adjusting" to his "new surroundings" at the White House.
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It was not clear when exactly the incident occurred, but video footage and photographs showed the animal being walked on a leash through the South Lawn by an aide around 5pm on Monday.
The Independent has reached out to the White House for a comment.
The Biden family adopted Major in 2018, and they also own a 12-year-old German shepherd named Champ.
Major was already involved in a separate biting incident on 8 March while living at the White House. At the time, he injured a Secret Service agent badly enough for the agent to seek treatment at the White House medical unit.
When speaking about the previous incident, White House Press Secretary Jen Psaki called it a “minor” injury that happened because the dog encountered someone that was unknown to him.
But shortly after the incident, both Champ and Major returned to the Biden family’s Delaware home while Mrs Biden was traveling away from the White House. Ms Psaki called this a planned trip for the dogs, but Major also received training at the time before returning to the residence.
“Major was a rescue pup. Major did not bite someone and penetrate the skin. The dog’s being trained now with our trainer at home in Delaware,” Mr Biden told ABC News earlier this month.
The president clarified that the dog was not “banished” to Delaware because of the incident.
“He was going home. I didn’t banish him to home. Jill was going to be away for four days. I was going to be away for two, so we took him home,” Mr Biden said.
“He’s a sweet dog,” the president added. “Eighty-five per cent of the people there love him. All he does is lick them and wag his tail.”
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