Other workers were trampled as they tried to rescue the man, and customers stepped over him and became irate when officials said the store was closing because of the death, police and witnesses said.
At least four other people, including a woman who was eight months pregnant, were taken to hospitals for observation or minor injuries, and the store in Valley Stream on Long Island closed for several hours. It reopened shortly after 1 p.m.
Bentonville, Ark.-based /*Wal-Mart*/ Stores Inc. called the incident a "tragic situation" and said it had tried to prepare for the crowd by adding staffers and outside security workers, putting up barricades and consulting police.
"Despite all of our precautions, this unfortunate event occurred," senior Vice President Hank Mullany said in a statement. "Our thoughts and prayers go out to the families of those impacted."
But Fleming said the store didn't have enough security.
Police said about 2,000 people were gathered outside the Wal-Mart doors before its 5 a.m. opening at a mall about 20 miles east of Manhattan. The impatient crowd knocked the employee, identified by police as Jdimytai Damour of Queens, to the ground as he opened the doors, leaving a metal portion of the frame crumpled like an accordion.
"This crowd was out of control," said Fleming, who described the scene as "utter chaos."
Dozens of store employees trying to fight their way out to help Damour were also getting trampled by the crowd, Fleming said. Witnesses said that even as the worker lay on the ground, shoppers streamed into the store, stepping over him.
Kimberly Cribbs, who witnessed the stampede, said shoppers were acting like "savages."
"When they were saying they had to leave, that an employee got killed, people were yelling, 'I've been on line since yesterday morning,"' she said. "They kept shopping."
The 34-year-old Damour was taken to Franklin Hospital Medical Center, where he was pronounced dead at about 6 a.m., police said. The exact cause of death has not been determined.
Damour came from a temporary agency and was doing maintenance work at the store, Wal-Mart said.
The 28-year-old pregnant woman was taken to a hospital, where she and the baby were reported to be OK, said police Sgt. Anthony Repalone. At least three other people were taken to hospitals with minor injuries.
Suffolk County police said a shopper at a Wal-Mart in Farmingdale, about 15 miles east of the Valley Stream location, reported being trampled by overeager customers at around the same time Damour was killed. The woman suffered minor injuries but finished shopping before she filed the report, police said.
Wal-Mart security varies by store. Officials wouldn't say how many security workers were at the Valley Stream location.
The retail giant has rigorously resisted being unionized. But the United Food and Commercial Workers Union Local 1500 termed the death "avoidable" and called for federal and state labor authorities to investigate. Union president Bruce Both said the store had failed to provide a safe workplace.
The National Retail Federation, the industry's largest group, was unaware of any other store workers ever dying on the job in the post-Thanksgiving rush, spokeswoman Ellen Davis said.
Shoppers around the country line up early outside stores on the day after Thanksgiving in the annual bargain-hunting ritual known as Black Friday. It got that name because it has historically been the day stores broke into profitability for the full year.
Many stores open early and stay open late on Black Friday. The Valley Stream Wal-Mart usually opens at 9 a.m.
Items on sale at the Wal-Mart store included a $798 Samsung 50-inch plasma HDTV, a Bissel compact upright vacuum for $28, a Samsung 10.2 megapixel digital camera for $69 and DVDs such as "The Incredible Hulk" for $9.
The store was crowded Friday afternoon after the store reopened, but shoppers were more subdued. It wasn't immediately clear whether there was additional security.
AP retail writers Anne D'Innocenzio and Mae Anderson and contributed to this report.