Commissioner Alan Bersin told President Obama on Thursday that he plans to resign, effective Dec. 30, the agency said in a statement.
"I have expressed my deep gratitude and appreciation to President Obama and [Homeland Security] Secretary [Janet] Napolitano for the opportunity to have led such an exceptional organization and for the confidence they have shown in me," Bersin said in the agency statement. CBP Deputy Commissioner David Aguilar will serve as the interim commissioner until Bersin's successor is appointed, according to agency officials. CBP would not immediately comment on the reason for Bersin's resignation.
"I am immensely proud of the significant and meaningful achievements we have made on our borders and at our nation's ports of entry over nearly two years," Bersin added.
The Senate failed to confirm Bersin after he received a recess appointment from Obama in March 2010. Prior to serving as commissioner, he served as "border czar" in both the Obama and Clinton administrations, where he was tasked with improving security along the U.S.-Mexico border.
Bersin could only serve through 2011 unless he was confirmed by the Senate after his recess appointment. Because Congress did not recess for a December holiday, Bersin could not receive a second recess appointment, said former CBP Commissioner W. Ralph Basham.
Basham called Bersin's resignation "a sad state of affairs."
"A great number of people felt Alan was doing an outstanding job and I believe he was. I believe that what's happened here is that politics got in the way of common sense," Basham said in an interview.
Basham, along with other former CBP commissioners penned several letters to lawmakers on the Senate finance committee, urging Bersin's confirmation.
"We are concerned about further delays in confirming Mr. Bersin to fill this critical national security position and the resulting uncertainty that it creates," the commissioners wrote in a June 2010 letter.
Bersin also served as co-chairman of a joint Labor Management Forum with the National Treasury Employees Union and CBP.
"NTEU worked closely with Commissioner Bersin on the issues that were critical to CBP and its mission, and that impacted frontline employees," NTEU President Colleen Kelley said in a statement Thursday.
"He had the utmost respect for employees and made that clear at every opportunity. He will be missed," Kelley said.