The head of the Department of Correction has resigned amid a series of revelations that raised questions about his competence and integrity.

A Department of Investigation report last week indicated that Commissioner Joseph Ponte logged 18,000 miles on his city car outside of New York City, mostly in the course of trips to his former home state of Maine, and spent more than $1,500 on gas and tolls on the city's tab. The investigation showed that Ponte was out of state for more than 90 days in 2016, including 35 during the work week, of which he formally took only six off. He did not return for an escape, an inmate death, the on-duty death of a DOC staffer, or a rash of knifings.

A document obtained by the Daily News showed that Ponte also traveled to the Buffalo area and Cape Cod.

A subsequent report accused Ponte's anti-corruption deputy of eavesdropping on city investigators' calls to jail informants. Ponte did not discipline the deputy prior to the report's release, but demoted him following its publication.

Speaking to Politico following the emailed announcement this afternoon, Ponte said. "At the end of the day, I feel there is no way to win a battle in the media, so it’s not about me—this is about the Department of Correction. I want this organization to be successful, people have done a lot of hard work, and if I stay or go, stay a minute or leave tomorrow, I want to leave it in the best place possible."

Regarding the trips to Maine, he said:

Lapse of judgment. I’m not trying to steal anything from anybody, they gave me a great salary to do this job, so I didn’t do that intentionally. I didn’t hide it, it was public knowledge. I don’t want to become the issue for the agency, these issues are mine to bear and I will, and the agency has a great potential to move forward in a positive way.

Ponte still has not explained why he traveled to Maine so much or what exactly he did there.

At a City Council hearing this week, Ponte said that he has yet to read the report released in early April outlining recommendations for closing the jail facility at Rikers Island. He also said that two aides and his driver told him it was kosher to take his city car out of town, which the aides said is a lie.

As calls for Ponte's resignation mounted, Mayor de Blasio stood staunchly behind him, "All people want to talk about is the godforsaken cars," de Blasio said to WNYC host Brian Lehrer on Thursday. "I feel like when Bernie Sanders said in that debate, 'Enough with the damn emails!' The car isn’t the issue — the issue is, has he made our correction system better?"

The mayor said that the public should be more focused on reforms that Ponte oversaw, including reducing the use of solitary confinement, banning its use on inmates younger than 22, and expanding education, mental health, and jobs programs.

"He has my confidence," de Blasio continued, "and I think he has done really good work for this city."

He blamed the continuing increases of stabbings and other violence on "decades of mistakes that we inherited."

De Blasio also had not read the report on closing Rikers as of Thursday, he told Lehrer, but he said he has been "thoroughly briefed."

In a statement this afternoon, de Blasio said, "New York City owes a debt of gratitude to Commissioner Ponte for his tireless efforts to change the culture and improve the effectiveness of one of the nation’s most challenging jail systems. While much work remains, there is no doubt that our city’s jails are safer, more rehabilitative, and more humane as a result of Commissioner Ponte’s work."

This story has been updated.