On Monday, Judge Robert Henney found Xolile Mngeni (25) guilty of robbery with aggravating circumstances, premeditated murder and illegal possession of a firearm and ammunition.
He was acquitted on a kidnapping charge as this was executed as part of a single chain of events leading up to the murder.
Dewani was killed in Gugulethu on November 13 2010, and her body found the next day.
"The state has proven its case beyond reasonable doubt," Henney said.
"The case against the accused is overwhelming and the accused could barely avoid the avalanche of evidence from crashing down on him."
Mngeni stood expressionless as the judgment was delivered. His family watched wide-eyed from the gallery above.
Hordes of photographers crowded around Mngeni when he walked back down to the cells, using his walking frame.
Fingerprints condemn Mngeni
Mngeni had pleaded not guilty to hijacking, robbing and killing the tourist, who had been on honeymoon with her husband Shrien at the time.
Mziwamadoda Qwabe and shuttle driver to the Dewanis, Zola Tongo, had already been convicted of the murder and were sentenced in terms of a plea agreement.
Henney said Mngeni was linked to the crime scene by his prints.
"Although initially vehemently denied as the fingerprint of the accused, this fact was later conceded. It can therefore be safely accepted that this was the left palm print of the accused."
A total of 26 witnesses were called by the state to strengthen its case.
The defence disputed the evidence of six witnesses. One of the witnesses was the middleman who helped set up the murder. His identity was being protected in terms of a court order.
Earlier, Henney said it needed to be remembered that Shrien Dewani had not yet been charged and no direct evidence was presented against him as it was Mngeni's trial. Shrien was in the process of being extradited from the United Kingdom.