The report said Farah submitted a letter of resignation to the White House on Thursday, following three-and-a-half years of working within the Trump administration.
Other Trump administration officials also announced their departures this week.
Scott Adams resigned from his position as a Trump special adviser on the coronavirus pandemic.
Federal Communications Commission (FCC) head Ajit Pai said in a statement on Monday that he has handed in his resignation and will step down on January 21.