"Doing something unethical is not in my DNA, it is not part of my track record", Long told reporters at a briefing on the storm.
The investigation has come to light at the same time that Long has become the face of the administration's effort to prepare for Hurricane Florence and its aftermath - a consequential test of President Donald Trump's leadership and of FEMA itself, after harsh criticism of the federal response to a hurricane that devastated Puerto Rico in 2017.
Politico said Long began using a staff driver for those journeys when his term began a year ago, and that aides also traveled with him at taxpayer expense.
At the beginning of his tenure at FEMA a year ago, Long started using a staff driver to get him back home to Hickory, North Carolina, according to Politico.
"I'm very aware of a recent article in regards to an ongoing investigation by the OIG in regards to FEMA vehicle usage", Long said.
Police enforce a mandatory evacuation in Wrightsville Beach, North Carolina.
World Cup victor Lloris 'completely drunk' at wheel
Dele suffered a muscle strain while being on national duty for England and the news had put Spurs fans on the edge of their seats. Lloris admitted being more than twice above the drink-drive limit when he was stopped by police in central London last month.
Long, the DHS IG's office, and the White House all did not respond to Politico's requests for comment.
The head of FEMA said he would never intentionally break government rules following a report that his use of official vehicles was under scrutiny, but that right now, he was focused on a major hurricane approaching the U.S. Southeast coast.
If their homes are damaged, FEMA has options beyond standard temporary trailers for housing, agency officials said.
Long said the inspector general was looking into vehicle usage, but he didn't confirm that the review concerned his use of an official vehicle.
Jessica Nalepa, FEMA director of external affairs, also responded to the investigation saying FEMA "fully cooperates with all investigations conducted by the DHS OIG".
Long reportedly began having a government driver take him home since he took control of FEMA past year.
Other Trump Administration officials have been investigated for ethics issues related to travel. Former Health and Human Services Secretary Tom Price, former Veterans Affairs Secretary David Shulkin and former EPA Administrator Scott Pruitt were all felled in part due to their own lavish travel scandals.