Judge Chertoff was praised by lawmakers from both parties during an appearance before the Senate committee that has oversight of the Homeland Security Department.
The former prosecutor and Justice Department official has been nominated by President Bush to replace Tom Ridge, who was the first Secretary of Homeland Security after the department was established by Congress after the 2001 terrorist attacks.
As a first priority, Judge Chertoff sought to reassure Senators on the committee from both parties that he is committed to protecting the civil liberties of Americans, even as he seeks to secure the country from terrorist attack.
"I believe that we cannot live in liberty without security," Mr. Chertoff said. "But we would not want to live in security without liberty. So we need both of those to fashion the architecture of our civilization going forward."
Some Democrats expressed concern about Judge Chertoff's tenure as head of the Justice Department's Criminal Division following the 2001 attacks. During that time, the department detained hundreds of illegal immigrants suspected of possible links with terrorism.
Democrats also urged the incoming security chief to press for more government funding within the Republican Bush administration.
"The department has to receive adequate financial support to carry out the enormous responsibilities we have given you in law to protect the American people from an enemy, terrorists, who will strike us where we are vulnerable," said Senator Joe Lieberman, a Democrat from Connecticut.
Committee Republicans praised the job done by outgoing Secretary Tom Ridge. But Virginia Republican John Warner told Judge Chertoff that the Homeland Security Department must continue to improve in a number of areas to keep the country safe.
"And I think the work that has been done by Secretary Ridge and many others have heavily contributed to deterring a major attack. But we will have to sleep with one eye open for the indefinite future," he said.
A vote by the full Senate confirming Judge Chertoff as a member of the president's cabinet is expected in the near future.