Jeffrey Skilling, 64, was sentenced to 24 years in prison in 2006 for his role in the collapse of the shuttered Houston energy company. He was also fined $45 million.
On May 25, 2006, a jury found Skilling guilty on one count of conspiracy, one count of insider trading, five counts of making false statements to auditors, and 12 counts of securities fraud.
ORIGINAL REPORT: Skilling released from prison
He was found not guilty on nine counts of insider trading.
Skilling's sentence was reduced in 2013 to 14 years.
The collapse of Enron put more than 5,000 people out of work, wiped out more than $2 billion in employee pensions, and rendered $60 billion in Enron stock worthless.
LOOKING BACK: Remembering the collapse of Enron
VIDEO: Jessica Willey reports on Enron filing bankruptcy.