The incident occurred "at the end of the day," Friday, around 11:38 p.m. officials told Fox News.
It is believed President Trump was asleep in the White House when the incident occurred.
The intruder remains unidentified and it's anyone's guess what his motive might have been. He scaled the outer-perimeter fence on the complex's southeast side and was arrested without incident. An officer in the agency's Uniformed Division made the arrest.
The man was carrying a backpack and was able to get close to the White House's south portico residence entrance on the Washington Monument side of the complex.
There was no hazardous material found inside the backpack and a search of the complex grounds resulted in "nothing of concern to security operations," the Secret Service said.
The intruder has no "previous history" with the agency, according to the Secret Service.
Homeland Security Secretary John Kelly was briefed on the incident.
There is currently no status update regarding the individual, and he will likely be handed over to local police as is standard procedure.
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