Embattled Secret Service chief Kimberly Cheatle has announced she will resign from her post less than two weeks after the agency’s calamitous failure at Donald Trump’s July 13 campaign rally led to him being wounded by an assassin’s bullet.

Cheatle, a 28-year veteran of the agency, faced mounting pressure to step down in recent days but insisted all along she would remain on the job. She announced her resignation in a letter to agency staffers on Tuesday morning.

“I have, and will always put the needs of this agency first. In light of recent events, it is with a heavy heart that I have made the difficult decision to step down as your Director,” Cheatle wrote in the letter, which was obtain by The Post.

She said she didn’t want the growing calls for her resignation to be “a distraction from the great work each and every one of you do towards our vital mission.”

Following the rally shooting — which left the former president nicked in the ear, two supporters badly wounded and a volunteer firefighter dead — Cheatle made a series of missteps that did little to reassure lawmakers or the American public that she was fit to remain in the role.

Among her baffling remarks was an admission to ABC News that the reason Secret Service agents weren’t posted on the roof from which Thomas Matthew Crooks fired on the rally crowd was because it was too “sloped,” creating an unacceptable “safety factor” for the agents.

The agency’s failure to adequately secure the roof gave the 20-year-old an unobstructed line of sight to the GOP standard bearer, leading to the first assassination attempt against a sitting or former US president since 1981.

At a House Oversight Committee meeting yesterday, Cheatle admitted the agency’s rally response was a “failure” but still gave her agents an “A” grade for the job they did that day.

Minutes before the news broke, House Speaker Mike Johnson (R-Calif.) had said he would not support impeaching Cheatle, though Rep. Nancy Mace (R-SC) had pushed for it a day before.

“Impeachment, as we know, is reserved for treason, bribery, high crimes and misdemeanors,” he said. “Maladministration and utter incompetence, unfortunately, are not impeachable offenses – but there are other ways to achieve the desired end.”

Notified of her resignation mid-briefing, he joked that Cheatle “must have been watching our press conference,” calling it the “right thing.”

“Look, our reaction, the immediate reaction to her resignation is that it is overdue. She should have done this, at least a week ago,” he said.

This is a developing story. Check back for updates.