John Pistole, the head of the Transportation Security Administration (TSA), announced Thursday that he is stepping down from his post at the end of December after more than four years on the job.
"It has been an honor and a privilege to have served as TSA Administrator," Pistole said in a statement. "I could not be more proud of all that our employees have accomplished together, particularly what they have done to help enhance the effectiveness and efficiency of transportation security while improving the passenger screening experience."
Before joining the TSA, Pistole spent 26 years at the FBI. He is expected to be named to an academic position in early 2015, according to the TSA.
Homeland Security Secretary Jeh Johnson, who oversees the TSA, thanked Pistole for his service in a statement.
"Because of his efforts over the past four and a half years, our country's transportation systems are more safe and secure," Johnson said. "I am grateful for John's contributions to DHS, TSA and our country."
During his tenure, Pistole oversaw significant changes in the passenger-screening process at the nation's airports. Some of those changes were controversial, including the installation of new body-scanning machines, and the requirement for individuals who refused the body-scan to undergo a manual pat-down. Both practices sparked an outcry from critics who felt they were too invasive. In 2013, Pistole announced that the TSA would remove some body-scanning machines from airports due to concerns about privacy.
Despite the controversy, Pistole generally received high marks on Capitol Hill for his stewardship of the agency.
"I commend Administrator Pistole for the outstanding job he has done as head of the Transportation Security Administration," said House Homeland Security Chairman Michael McCaul, R-Texas, in a statement. "Mr. Pistole shared my goal of refining TSA to better serve travelers' needs, while still providing safe mass transit. With more than 30 years with the FBI and TSA, he has shown a dedication to the security of his country few can match. I wish him and his family all the best in his future endeavors."