The Republican-led Senate rejected on Thursday Democrat complaints that Gonzales helped craft policies that contributed to the torture of foreign detainees, and approved him on a largely party-line vote of 60-36.
A former Texas Supreme Court justice and President George Bush's top lawyer for the past four years, the 49-year-old Gonzales was quickly sworn in at the White House as the first Hispanic to head the Justice Department.
Bush nominated Gonzales to replace his first attorney-general John Ashcroft, a conservative lightning rod barely confirmed
four years ago by a 58-42 vote.
The only attorney-general nominee with more no votes was Charles Warren, whose nomination was rejected by the Senate in March 1925 by 39-46, according to the Senate historian's office.
Senate Democrats opposed Gonzales, charging that detention policies he helped craft after the 11 September 2001 attacks contributed to the abuse of foreign detainees and put Americans at increased risk.
Though Democrats could not stop Gonzales, some said they hope the big no vote will help dissuade Bush from possibly nominating him in the future to the US Supreme Court.
The battle over Gonzales has focused largely on a 1 August 2002 memo he approved that gave a narrow definition to torture. The memo was later withdrawn and replaced.
Gonzales also was criticised for writing in January 2002 that parts of the half-century-old Geneva Convention on the treatment of prisoners of war were "obsolete" and "quaint".