Washington (CNN) -- It's been a long time coming -- one year, five months and 10 days, to be precise.
But the Transportation Security Administration will get its new chief Thursday when Homeland Security Secretary Janet Napolitano swears in John Pistole during a rail security event at New York's Pennsylvania Station.
Pistole, second in command at the FBI, sailed through a Senate confirmation process earlier this month after two previous nominees withdrew from consideration amid allegations of improprieties. The missteps left the agency -- which includes the nation's 50,000 airport screeners, thousands of air marshals, and others -- with an acting chief for almost a year and a half, a time marked by a series of transportation-related security scares, most notably the Christmas Day airplane bombing attempt.
"It's embarrassing, you know, that such an enormous undertaking doesn't have the leadership that it needs," Sen. John D. Rockefeller, D-West Virginia, said upon opening Pistole's confirmation hearing earlier this month.
"We need an experienced and skilled administrator and we need that person now to lead the TSA," Rockefeller said, "because people can work hard, but if they don't have a leader, something happens to them eventually."
Pistole was confirmed by the U.S. Senate last week. A career official with the FBI, Pistole was appointed head of the bureau's counterterrorism division after the September 11, 2001, terrorist attacks.
Pistole received bipartisan support during his confirmation hearings, but earlier nominees fell under the weight of Republican attacks. The president's first pick, Erroll Southers, then a top official of the Los Angeles Airport Police department, withdrew after revelation of a decades-old personnel matter. Obama's second nominee, retired Army Maj. Gen. Robert Harding, stepped down amid questions about contracts received by a firm he founded after his retirement.
Both Southers and Harding denied wrongdoing, and supporters say their nominations were complicated by the president's pledge to unionize the legions of TSA airport baggage screeners. Republican legislators, led by Sen. Jim DeMint of South Carolina, oppose unionization, saying it will make the agency less nimble in responding to terrorist threats.
Negotiated contracts could prevent managers from quickly moving union personnel and resources, they said.
Supporters of unions said contracts can protect workers while maintaining security, adding that most other federal law enforcement agencies, including the U.S. Border Patrol, have been unionized.
Pistole has said he is well-versed in the counterterrorism mission, having helped lead the investigation into EgyptAir 990, which crashed off the coast of New England in 1999, and a 2003 investigation into the bombing of three Western housing compounds in Riyadh, Saudi Arabia.
Pistole testified that his top priority at the TSA is "to ensure that the men and women of TSA and all those who deal with it see it as a threat-based, intelligence-driven agency with a national security focus."
"What it comes back to is making sure that TSA has the latest intelligence, the latest training, the latest techniques and the latest technology to work as part of that layered defense," he said.