Customers queued before dawn in many cities to snap up cut-price flatscreen TVs, laptops, hooded sweatshirts, smartphones and other popular items. Retailers reported larger crowds than last year, raising hopes that the number of people out shopping could exceed the National Retail Federation's forecast of 138 million.
Traditionally, the day after Thanksgiving marks the point when US shops go into profit, or into the black, for the calendar year. Some major stores, including cut-price chains Kohl's and JCPenney, opened their doors as early as 3am.
Instant figures from IBM Coremetrics, which gathers data from retail websites, suggested that online sales were up by 5% by mid-afternoon on Friday. And the analysis firm reported that web sales on Thursday's US public holiday leapt by 33%. Jerry Storch, chief executive of Toys R Us, which opened some shops at 10pm on Thursday to trade all night, said his chain was "off to a strong start". The boss of Macy's department stores, Terry Lundgren, said people were shopping for personal indulgences, rather than merely buying early Christmas presents: "Here is Black Friday, the kickoff of the holiday gift-giving season, and shoppers were shopping for themselves."
The world's biggest economy is still struggling to fight its way out of an economic rut: unemployment is stuck at 9.6% but consumer confidence has edged slightly higher in recent months.
Read More: Bumper Black Friday in prospect as America goes to the sales
