"It's an important tool for us to continue dealing with an ongoing terrorist threat," Obama said Friday after a meeting with French President Nicolas Sarkozy.
Congress passed the legislation in rapid succession votes on Thursday. They were up against a midnight deadline that would have seen three key terrorism-fighting powers expire. They include the use of roving wiretaps, access to business records and allowing surveillance of non-American terror suspects.
The Senate voted 72-23 for the legislation to renew three terrorism-fighting authorities. The House passed the measure 250-153 on an evening vote.
Following the vote in the House, Obama, who was in France, signed the bill using an autopen machine that holds a pen and signs his actual signature, according to the White House. It is only used with proper authorization of the president.
A short-term expiration would not have interrupted ongoing operations but would have barred the government from seeking warrants for new investigations.
Congress bumped up against the deadline mainly because of the resistance from a single senator, Republican freshman Rand Paul of Kentucky, who saw the terrorist-hunting powers as an abuse of privacy rights. Paul held up the final vote for several days while he demanded a chance to change the bill to diminish the government's ability to monitor individual actions. The bill passed the Senate 72-23.
The roving wiretaps and access to business records are small parts of the USA Patriot Act enacted after the Sept. 11, 2001, attacks. But unlike most of the act, which is permanent law, those provisions must be renewed periodically because of concerns that they could be used to violate privacy rights.
The Associated Press contributed to this story.
