WASHINGTON — The director of the Secret Service announced on Thursday that he would retire at the end of the month after a 27-year career with the agency that is charged with protecting the president of the United States.

The director, James M. Murray, has accepted a position with the social media company Snap, which is known for its messaging app, Snapchat, an agency spokesman said.

Mr. Murray was appointed by President Donald J. Trump in 2019 after Mr. Trump became disillusioned with the agency’s director at the time, Randolph D. Alles. The director of the Secret Service is appointed by the president and does not require Senate confirmation.

“Joining the Secret Service was the easiest decision I have ever made,” Mr. Murray wrote in a letter to agency employees on Thursday. “Deciding it is time to move on, however, has been one of the most difficult.”

In April, Mr. Murray told the homeland security secretary, Alejandro N. Mayorkas, whose sprawling department includes the Secret Service, that he planned to retire and take a job outside of government, Mr. Murray said in the letter.

In a joint statement, President Biden and the first lady, Jill Biden, expressed appreciation to Mr. Murray. “We are incredibly grateful for his service to our country and our family,” they said.

The Secret Service has come under the spotlight in recent days after more details emerged about Mr. Trump’s actions on Jan. 6, 2021, when a mob of his supporters attacked the Capitol in an effort to stop the routine process of certifying the results of the presidential election.

Mr. Trump’s protective detail was with him throughout that day. In testimony last week before the House committee investigating the attack, a former White House aide said she was told that Mr. Trump tried to grab the steering wheel of the presidential vehicle and lunged at his lead Secret Service agent after being told he could not go to the Capitol.