Martin Shkreli's cohort in crime may be a "mensch" and an Eagle Scout who's devoted his life to serving others, but that didn't save Evan Greebel from a prison sentence for aiding the Pharma Bro in an $11 million ($15 million) fraud.

Greebel on Friday was ordered to serve 18 months behind bars for conspiring with Shkreli, as U.S. District Judge Kiyo Matsumoto in Brooklyn, New York, turned aside his plea to remain free.

Evan Greebel (on right, in white shirt) with Martin Shkreli (second from left) and their defense attorneys in court as they faced their conspiracy charges. Credit:AP

"I will regret every day of my life the day that I met Martin Shkreli," Greebel told the judge. "But I want to be clear, I only hold myself responsible."

Greebel was convicted last year of helping Shkreli steal $US11 million to repay investors after the hedge-fund-manager-turned-drug-executive, lost their money in risky trades. Greebel, a New York attorney, was the outside counsel to Retrophin, which Shkreli co-founded.