The 61-year-old former football star was convicted of all 12 counts late Friday after jurors deliberated for more than 13 hours. He released a heavy sigh as the charges were read and was immediately taken into custody.
Simpson, who went from American sports idol to celebrity-in-exile after his murder acquittal, could spend the rest of his life in prison.
Many people considered the four-week trial justice delayed. Simpson was cleared in 1995 of murdering his ex-wife, Nicole Brown Simpson, and her friend, Ronald Goldman, in one of the most sensational trials of the 20th century, but was later found liable for the deaths in a civil case.
"This was just payback," Simpson lawyer Yale Galanter said Saturday. "They were on an agenda."
Galanter said he plans to appeal.
The Hall of Fame football star was convicted of kidnapping, armed robbery and 10 other charges for gathering up five men a year ago and storming into a room at a hotel-casino, where the group seized several game balls, plaques and photos. Prosecutors said two of the men with him were armed; one of them said Simpson asked him to bring a gun.
Simpson's co-defendant, Clarence "C.J." Stewart, 54, also was found guilty on all charges and taken into custody.
Simpson showed little emotion as officers handcuffed him and walked him out of the courtroom. His sister, Carmelita Durio, sobbed behind him in the arms of Simpson's friend, Tom Scotto, who said "I love you" as Simpson passed by. As spectators left the courtroom, Durio collapsed.
Jurors made no eye contact with the defendants as they entered the courtroom. They declined to answer questions after the verdict was read.
Galanter said his client had expected the outcome, and in a courthouse conversation with an Associated Press reporter on Thursday, Simpson had implied as much.
Simpson said he was "afraid that I won't get to go to my kids' college graduations after I managed to get them through college."