Fratto, known as "the Chin," pleaded guilty to federal tax evasion after admitting he failed to pay more than $140,000 in federal taxes from 2001 to 2007.
U.S. District Judge Harry Leinenweber could have sentenced Fratto on Wednesday to more than two years.
Evidence included wiretaps where Fratto is heard cursing as he talks about breaking someone's legs. At one point he brags about how "guys" as far away as Cleveland appreciate his influence.
In asking for leniency, the defense cited Fratto's ailing health and remorse.
The Darien man pleaded guilty last year. He must report to prison Jan. 8.
The Associated Press contributed to this report.