WASHINGTON — The Obama administration’s top drug enforcement official will step down next month, Attorney General Eric H. Holder Jr. announced on Tuesday, after her agency was tarnished by a scandal over sex parties with prostitutes and she broke with President Obama on drug policy.

Michele M. Leonhart, the administrator of the Drug Enforcement Administration, told Mr. Holder that she intended to retire, ending a 35-year tenure at the agency. In a statement, he called her a “trailblazer for equality” and a “good friend,” but in recent years, she had faced accusations of mismanagement.

Ms. Leonhart’s impending departure after eight years in the top job follows a hearing last week in which lawmakers on the House Oversight Committee expressed outrage about her handling of reports that D.E.A. agents in Colombia had participated in sex parties with prostitutes paid for by drug cartels.

It also comes after Ms. Leonhart, 59, parted with the White House on marijuana policy, opposing moves by states like Colorado and Washington to legalize its use, even as the president said they should be allowed to go forward, and resisting a push to reduce penalties for its use and distribution.