While retailers didn't provide immediate sales figures, they indicated their decisions to start Black Friday sales a day early, on Thanksgiving Day, were successful.
Walmart Stores Inc. said it recorded more than 10 million in-store register transactions between 6 p.m. and 10 p.m. Thursday and nearly 400 million page views on Walmart.com, The Wall Street Journal said.
Rival Target Corp. said online sales were among its highest for a single day.
More than a dozen major retailers, including Walmart and Target, opened on the holiday in an effort to boost struggling sales in a tight economy and keep up with online retailers.
J.C. Penney Co. and Macy's Inc. opened their doors on Thanksgiving for the first time.
Other retailers, such as Gap Inc., which owns Banana Republic, Gap and Old Navy, opened stores earlier on Thanksgiving than last year.
Target, Penney, Toys "R" Us and Sears Holding Corp.'s Sears and Kmart stores were among the stores that stayed open all night.
Many retailers and some shoppers said the day-early start of the Black Friday bonanza made shopping less hectic, but shoppers reported lots of jostling and police reported some violence.
Several Walmart shoppers from across the country posted videos to YouTube showing in-store fights, mostly over big-ticket electronic products.
A police officer was injured outside a Walmart in Rialto, Calif., trying to defuse tensions over shoppers said to be cutting in line.
In suburban Chicago, a police officer responding to a call of alleged shoplifting at a Kohl's Corp. store Thanksgiving night shot the driver of a car that was dragging a fellow officer, police said.
The driver, 52, was wounded in the left arm, Romeoville, Ill., police said. He and a passenger and a third suspect in the store were arrested.
Felony charges were filed against the passenger and third suspect, police said. The driver, treated for his gunshot wound at a hospital, was not immediately charged, the Chicago Tribune said.
The dragged officer was treated and released from a different hospital.
He was dragged after chasing the driver to his car. The driver then "closed the car door on the officer's arm, not allowing the officer to disengage from the vehicle," police said in a statement. "The driver then drove away, dragging the officer with the vehicle."
A man in Las Vegas was shot in the leg by an alleged thief who stole his big-screen TV, police said.
The victim was carrying his purchase home when a man with a gun approached him and fired warning shots that caused the victim to give up the TV, police spokesman Lt. David Gordon told NBC News.
As the thief tried to load it into a vehicle, the victim approached him to try and get the TV back, Gordon said.
This time, "The suspect fired two more shots and the victim was struck in the leg," he said. "He was not seriously injured."
In another injury, a 35-year-old man was stabbed in the arm during an argument outside a Walmart in Claypool Hill, W.Va., police told Bluefield (W.Va.) Daily Telegraph.
Both men were arrested -- the suspect on charges of malicious wounding and brandishing a firearm and the victim on charges of disorderly conduct and assault and battery.
About 97 million people were expected to shop in stores and online Friday, the National Retail Federation said. By the time the four-day holiday weekend is over, some 140 million people will shop, the trade group said.
The figure is 7 million less than last year's 147 million.
Shoppers spent about $60 billion during last year's holiday weekend and more than 40 percent of that spending took place online, the federation said.
"Black Friday 2013 is here!" Amazon.com declared. "Black Friday starts now online!" Walmart.com said, touting both the website and its brick-and-mortar stores with "online-only specials" and store maps so customers could "plan your in-store Black Friday shopping trip."
Sears.com offered "1,000-plus Black Friday Door-Busters," with some prices dubbed "online-only savings." Customers were advised to key in their ZIP code to see if the discounted items they saw online were available at their local store.
Montgomery Ward Inc.'s Wards.com offered a "Generous Santa Sale," with savings on some items discounted up to 70 percent.
Retail chains, including Walmart and Macy's, have warned investors their profit margins may take a hit this season as they strive to increase market share.
At a Toys "R" Us Inc. store in Kingston, N.Y., an associate named Ed asked shoppers waiting in a long checkout line Thursday night if everyone was happy.
Customers gave him blank stares, the Times Herald-Record of Middletown, N.Y., reported.
"How about happy-ish?" Ed asked.
He got nods and tired smiles, the newspaper said.