A Kuwaiti policeman inspects the
victim's car (file)
The 25-year-old Sami Al-Mutairi was found guilty of a highway ambush on 21 January that killed Michael Rene Pouliot and seriously wounded David Caraway.
They were contractors for Camp Doha, the largest US army base in the emirate.
It was the second fatal attack against Americans in Kuwait since last October and the first to target civilians.
Defence lawyer Osama Al-Munawer said they would appeal the verdict, saying there was no proof presented during the trial indicating his client was guilty.
In Kuwait, a death sentence can be appealed in court twice before the Emir has to endorse it or dismiss it on the basis of mercy.
Al-Mutairi, who had pleaded not guilty, fled to Saudi Arabia where he was captured two days later and brought back to Kuwait.
An Interior Ministry statement released after his arrest said he admitted the crime. The court watched a confession tape in which Al-Mutairi said he did not regret the attack and would do it again if he were freed.
The court said Al-Mutairi had tried but failed to join al-Qaeda in Afghanistan and returned to Kuwait supporting the killing of Americans in the Emirate.
Two other men were sentenced to three-year prison terms for providing Al-Mutairi with a weapon and ammunition used in the attack.
Last October two Kuwaiti gunmen killed a US Marine and wounded a second during war games on Failaka Island, 20 kilometres east of the capital.
About 8,000 Americans reside in Kuwait. Also, tens of thousands of US troops invaded Iraq in March from the Emirate’s northern desert.
Anti-US sentiment was on the rise prior the US-led war against Iraq.