The jury ordered Samsung to pay Apple $1.05 billion. An appeal is expected.
Apple Inc. filed its patent infringement lawsuit in April 2011 and engaged legions of the country's highest-paid patent lawyers to demand $2.5 billion from its top smartphone competitor. Samsung Electronics Co. fired back with its own lawsuit seeking $399 million.
During closing arguments, Apple attorney Harold McElhinny claimed Samsung was having a "crisis of design" after the 2007 launch of the iPhone, and executives with the South Korean company were determined to illegally cash in on the success of the revolutionary device.
Samsung's lawyers countered that it was simply and legally giving consumers what they want: smartphones with big screens. They said Samsung didn't violate any of Apple's patents and further alleged innovations claimed by Apple were actually created by other companies.
Samsung has emerged as one of Apple's biggest rivals and has overtaken Apple as the leading smartphone maker. Samsung's Galaxy line of phones run on Android, a mobile operating system that Google Inc. has given out for free to Samsung and other phone makers.
Samsung conceded that Apple makes great products but said it doesn't have a monopoly on the design of rectangle phones with rounded corners that it claimed it created.
The trial came after each side filed a blizzard of legal motions and refused advisories by U.S. District Judge Lucy Koh to settle the dispute out of court.
Deliberations by the jury of seven men and two women began Wednesday.
Samsung has sold 22.7 million smartphones and tablets that Apple claimed use its technology. McElhinny said those devices accounted for $8.16 billion in sales since June 2010.
Together, Apple and Samsung account for more than half of global smartphone sales.