Defendant Mazen Alotaibi (MAH'-zen ah-loh-TAH'-bee) remained seated, clenching his jaw but showing no outward emotion as the verdict was read in Nevada state court.
The 24-year-old Royal Saudi Air Force mechanic, who had been in the U.S. for military training, will face a minimum mandatory 35 years in state prison at sentencing Dec. 16.
Clark County District Court Judge Stefany Miley could sentence him to prison for life.
The jury of nine women and three men found Alotaibi guilty of sexual assault with a minor for forcing oral and anal sex on the boy in the bathroom of a sixth-floor room at the Circus Circus hotel, and lewdness with a child for fondling and kissing the boy on the way to the room.
Alotaibi decided not to testify in his defense.
Jurors instead saw a 70-minute videotaped police interview in which Alotaibi told detectives the boy offered sex for marijuana or money. After several minutes of denials, Alotaibi acknowledged to police that he engaged in sex with the boy.
The Associated Press is withholding the boy's name because of his age and the nature of the case.
Nevada state law says a child under 16 can't give consent. But Alotaibi's lawyer, Don Chairez, said Alotaibi was too intoxicated after drinking all night at a strip club to know if he was doing anything wrong.
Chairez spoke with jurors after the verdict and said outside court that he will appeal.
"I believe, with hindsight, that it was a mistake not to have Mazen testify," Chairez said, explaining that he believes jurors were left with evidence that his client had forced the boy to have sex.
The defense attorney faulted himself for not fighting harder for the jury to be able to consider a lesser felony charge of statutory sexual seduction, which carries a possible sentence of probation or up to 10 years in prison.
Prosecutor Jacqueline Bluth said the state was happy with the outcome.
"We didn't believe this was consensual and that the defendant was drunk," she said.
The Saudi Royal Consulate General in Los Angeles didn't respond Wednesday to messages about the case.
A consulate official attended at least one January court appearance. Chairez said he has been in contact with consulate officials before, during and after trial, but no government representatives attended the proceedings.
Jurors heard five days of testimony and spent just five hours deliberating.
Alotaibi had been charged with nine felonies, but was found guilty of six felonies and one misdemeanor.
The jury acquitted him of two lewdness counts that were offered as lesser alternatives to the two most serious counts of sexual assault with a minor under 14.
Alotaibi was convicted of two other counts of lewdness with a child under 14 and one count of kidnapping, which each carry a possible sentence of 10 years to life in prison. He was also found guilty of felony burglary for entering a building with intent to commit a crime, and of misdemeanor coercion.
The boy testified that he was waiting to go to breakfast with a friend when he approached Alotaibi and other men early Dec. 31 in a hallway at the Circus Circus because he smelled marijuana on their clothes and wanted pot.
The jury heard that other men who lounged and smoked in the room shooed the boy away after learning that he was 13.
Alotaibi followed the boy, out of the room, smoked marijuana with him outside the hotel, and asked the boy for sex, according to the boy's account.
Alotaibi was seen on elevator surveillance video leaning down and apparently kissing the boy's neck on their way back to the hotel room. The boy is seen running back to the elevator about 30 minutes later.
The boy testified that in the hotel room bathroom, Alotaibi blocked the door, offered him $150 and then doubled the amount, and forced him into oral and anal sex.
A man who was traveling with Alotaibi testified that he knocked several times on the locked bathroom door while Alotaibi and the boy were inside, but they didn't come out.
Bluth told the jury that Alotaibi wanted sex and wouldn't take no for an answer.
Alotaibi rejected a plea deal before trial that could have gotten him a possible sentence of probation or up to 80 years in prison for pleading guilty to two charges each of felony attempted sexual assault and attempted lewdness.