In a statement released Wednesday night, the administration praised Nielsen for her "extensive professional experience" in homeland security policy, cybersecurity, critical infrastructure and emergency management.
"She is the first nominee for this position to have previously worked within the Department of Homeland Security, having served there in two administrations, first as senior legislative policy director for Transportation and Security Administration under President George W. Bush and then as Department of Homeland Security Chief of Staff under President Trump," the statement added.
The Department of Homeland Security was created in the wake of the terror attacks on September 11, 2001.
Former Pennsylvania Gov. Tom Ridge, the department's the first secretary, praised Nielsen's nomination.
"Kirstjen Nielsen is a homeland security veteran, who brings White House and DHS experience to the Secretary's role," Ridge said in a statement. "She is extremely well versed in the all-hazard threats challenging the security and resilience of our homeland -- from cybersecurity and terrorism to natural disasters."
News of Nielsen's expected selection was first reported
Nielsen previously worked as Kelly's chief of staff at the Department of Homeland Security and then followed him into the White House when he replaced Reince Priebus as Trump's White House chief of staff at the end of July. However, this was not her first time working in the White House, as she previously served in Bush's administration as the special assistant for prevention, preparedness and response on the Homeland Security Council.
Before being named DHS chief of staff in January, Nielsen was the president of Sunesis Consulting, a risk and security management consulting firm.
Acting DHS Secretary Elaine Duke was one of several candidates mentioned for the top DHS job along with Kobach, Sen. Tom Cotton, R-Arkansas, and Thomas Homan, the acting director of US Immigration and Customs Enforcement. Rep. Michael McCaul, a Texas Republican and chairman of the House homeland security committee, was also on the short list
, sources previously told CNN.
But Trump's public criticism of Attorney General Jeff Sessions and other episodes of White House chaos gave McCaul "pause," according to a source.
The DHS has had its hands full between dealing with security efforts following the string of hurricanes to hit the country and a recent administration decision to rescind the Deferred Action for Childhood Arrivals program.
Duke found herself in the middle of heavy criticism in late September after she made remarks about Hurricane Maria in Puerto Rico, saying the government's response was "a good news story