Randolph Alles is one of several Department of Homeland Security (DHS) officials being ousted on Monday, says the BBC's U.S. affiliate, CBS News.
The first sign of the overhaul came late on Thursday, when Trump abruptly pulled his nomination of Ron Vitiello as director of US Immigration and Customs Enforcement, part of DHS. The Secret Service director reports to the Homeland Security secretary.
"The purge of senior leadership at the Department of Homeland Security is unprecedented and a threat to our national security", Feinstein said in a statement.
Further ousters from the agency were reportedly imminent.
Some officials told the newspaper on Monday that although plans had already been made for Alles' removal before the arrest of a suspicious Chinese woman carrying malware was made at Mar-a-Lago last week, they believe the incident helped accelerate his leave.
"In addition to congressional dysfunction, I am concerned with a growing leadership void within the department tasked with addressing some of the most significant problems facing the nation".More news: White House pushes back on request for Trump tax forms
Ms Sanders said Mr Alles had done "a great job at the agency over the last two years" and Mr Trump was thankful for his service.
But Mr Alles's unfamiliarity with the agency led to conflicts, the officials said.
The Trump administration did not immediately respond to Newsweek's request for comment.
Trump selected Alles to head the Secret Service in April 2017.
Trump, seeking re-election in 2020, has taken a hard line toward immigration since becoming president in January 2017, and the issue may be a central theme in next year's race.
Trump all but fired Nielsen on Sunday after a heated exchange at the White House over whether she was expending all possible resources in dealing with the flow of thousands of migrants across the U.S. -Mexico border. The president would have had to place Grady in charge of DHS, given that she was the most senior Senate-confirmed official there. Trump said Kevin McAleenan, the current US Customs and Border Protection commissioner, will become acting secretary of the Department of Homeland Security.
Among those in the president's cross hairs are, reportedly L Francis Cissna with US Citizenship and Immigration Services and John Mitnik, the general counsel for the Secret Service. Trump was so frustrated about the increase that he announced he would cut off United States aid to Guatemala, Honduras and El Salvador.