"The special prosecutors actually made it easier for Samsung to get away," said Song Won-geun, an economics professor at Jinju National University, referring to their decision not to charge Lee with the most damaging accusation of bribery, settling instead with tax evasion.
Attempts to reach the prosecutors, who were not present at the verdict, were unsuccessful.
"South Korea's tradition to be lenient towards white-collar, economy-related crimes has distorted the economic order of the nation," said Rhie Sang-min of the People's Solidarity for Participatory Democracy, which has long been critical of the way the country's major conglomerates are run.
"It only further encourages economic crimes down the road."
A number of Samsung executives were present in the packed courtroom and showed visible signs of relief when the suspended verdict was read.
"I am sorry," Lee told reporters as he left the courthouse. Asked whether he was relieved at the verdict, he said: "I have to continue to feel responsible."
A spokesman for the Samsung Group declined to comment.
Lee, 66, stepped down in April from his top roles in the group and flagship Samsung Electronics, the world's leading maker of memory chips and LCD screens, after being indicted, but he remains a key shareholder in Samsung companies and his family wields powerful influence over the group.
Samsung group's firms account for 20 percent of total market capitalisation on the main board of the South Korean stock exchange. The group has more than 250,000 employees and its annual revenues of $160 billion are around the size of Singapore's gross domestic product.
A special prosecutor in January launched a probe into corruption allegations after a former top legal executive at the group said some of its top management hid money and kept a slush fund to bribe politicians, prosecutors and officials.
The prosecutor also indicted nine other top executives, but found no evidence to support the bribery allegations.
