Madeleine Westerhout, 29, was abruptly removed on Thursday after Trump learned she had shared the private details at a dinner with reporters earlier in August.
In one such incident, Westerhout was drinking and bragging about her access to Trump during his vacation in New Jersey, CBS News reported. She had worked with Trump since the first day of his presidency.
Described in the US media as Trump's gatekeeper, she had an office directly in front of his Oval Office in the West Wing. According to CBS, the President also often referred to her as "my beauty".
The White House declined to comment on her departure. The New York Times cited a White House source as saying that she is now considered a "separated employee" and would be barred from returning to the White House.
Westerhout disclosed the private details about the President's family in an off-the-record dinner conversation with reporters at an Embassy Suites hotel in Berkeley Heights, New Jersey, during Trump's vacation to his club in Bedminster, New Jersey, earlier in August.
"She was a spy from day one who sought to use her proximity to the President to curry favour with his detractors," said one former White House official.
Westerhout was reportedly earning $145,000 when she was terminated. She had previously worked for the Republican National Committee. During Trump's transition, she was often seen escorting guests through the lobby of Trump Tower in New York.
( With inputs from IANS )