The submarine's commanding officer, Capt. John Litherland, and crew of 134 officers and enlisted sailors obliged, running through an applauding crowd of thousands to stand atop the vessel and salute.
"Today, at long last, she and you are ready," she told the crew. She said she and the nation were "trusting you to remind the world 'Don't Mess with Texas."'
It is the fourth Navy ship to carry the name Texas.
"After a 13-year absence from the fleet, the proud name of Texas returns to the Navy," said Dionel Aviles, undersecretary of the Navy.
The nuclear-powered USS Texas began construction in 1999 and was delivered to the Navy in June. Its reactor is designed to not require refueling throughout the boat's service.
The 377-foot-long submarine can attack targets with Tomahawk cruise missiles and conduct long-term surveillance. It can dive to 800 feet.
"Texas is a very elegant ship, but it is very lethal," said Mike Petters, president of Northrop Grumman Newport News, the shipbuilder.
Sen. John Cornyn, R-Texas, said such strength is necessary in the nation's war on terrorism. The new submarine, he said, should "provide our war fighters with the tools for the job they have so nobly volunteered to perform."