Coast Guard Vice Adm. Thad W. Allen (search), tapped on Friday to head the federal government's response to Hurricane Katrina, has taken on big challenges before.

Allen was commander of all Coast Guard operations east of the Rocky Mountains on Sept. 11, 2001 (search). In the days after the terrorist attacks, he was responsible for making sure local responders in the New York area had the vessels, aircraft and personnel they needed.

He also is credited with leading the Coast Guard's smooth transition from the Transportation Department to the Homeland Security Department (search) in 2003.

Homeland Security Secretary Michael Chertoff (search) elevated Allen from a job he'd only been appointed to on Monday — special deputy for hurricane recovery efforts. Chertoff described Allen's position on Friday as the principal federal official overseeing the federal response and recovery effort.

"Vice Admiral Allen is doing an exceptional job, and he has my full support in the important work ahead," Chertoff said.

Chertoff noted that containing and cleaning up the oil spills created by Katrina on both land and sea will be an enormous challenge. Protecting the environment is one of the Coast Guard's main missions, along with search and rescue.

Allen will work with Army Lt. Gen. Russel Honore, who heads the military's Joint Task Force Katrina, to manage the military and civilian recovery efforts.

Allen, the Coast Guard's chief of staff since 2002, has spent his entire career in the Coast Guard since graduating from the U.S. Coast Guard Academy in 1971. He was director of resources under Adm. James Loy, who later became Homeland Security's deputy secretary.

A graduate of MIT's Sloan School of Management, Allen is described as sharp and incisive, an avid reader who provides clear direction.

"We don't know when he sleeps," said Coast Guard spokeswoman Jolie Shifflet.

He has been in charge of Coast Guard operations in South Carolina, Georgia, most of Florida and throughout the Caribbean.

Allen has a master's degree in public administration from George Washington University.

He is married to the former Pamela Hess, assistant dean for student services at the George Mason University School of Management. They have three grown children and two grandchildren.