PORTLAND — Portland defense attorney and sports agent Gary Prolman, the only lawyer to get an accused john acquitted in last year’s high-profile Kennebunk prostitution case, pleaded guilty on Tuesday to conspiring to launder money for a drug trafficker.

During a Tuesday afternoon appearance in U.S. District Court, Prolman pleaded guilty to a single charge of conspiracy to launder money for helping interstate marijuana trafficker David Jones funnel $177,500 in illegal drug proceeds through legitimate-seeming business deals.

Prolman faces a maximum sentence of 20 years in prison and $500,000 in fines, although a plea agreement reached with federal prosecutors allows him to appeal any sentence greater than 46 months behind bars.

U.S. Attorney Thomas Delahanty said in a Tuesday afternoon announcement that between June and September of 2012, Jones gave Prolman drug money to invest in the lawyer’s burgeoning sports agency business, to deposit in small amounts and cashier’s checks to avoid federal scrutiny, and to jointly buy real estate.

Assistant U.S. Attorney Daniel Perry represented the federal prosecution team before U.S. District Court Judge George Z. Singal during Tuesday afternoon’s hearing.

“Prolman received three separate $50,000 cash installment payments, largely consisting of low denomination bills delivered in a backpack,” Delahanty wrote, in part. “When Prolman attempted to deposit more than $10,000 from the first $50,000 installment into bank accounts he controlled, a bank teller advised him of the federal currency reporting requirement for deposits exceeding $10,000. … After being advised of the reporting requirement by the bank teller, Prolman structured numerous cash deposits [to be less than $10,000] and paid $60,409 to close the joint real estate purchase using seven structured cashier’s checks.”

Prolman declined to comment after Tuesday afternoon’s hearing in Portland, but his attorney, Peter DeTroy, said in a written statement Prolman “is profoundly and genuinely remorseful to his friends, family, clients, and the Maine community at large, for his current predicament, and any adverse impact he has caused anyone.”

DeTroy said the “specific circumstances that led to this guilty plea will have to await the sentencing hearing,” but said Prolman is willing to accept the consequences of his action and hopes to one day again become a “productive member of the community.”

“Through this plea, he wishes to acknowledge clearly and unambiguously that his actions in accepting monies from David Jones were wrong and constitute money laundering under federal law since the monies invested were derived from a marijuana conspiracy,” DeTroy said, in part.

“Since the inception of the investigation by the U.S. attorney’s office nearly 1½ years ago, he has sought to be transparent and own up to his mistakes,” DeTroy continued. “Although this has been a personally humiliating and painful experience, by this plea today, he is one step closer to bringing closure to this difficult chapter in his life for himself, family and friends who also have had to endure this process.”

Jones, who reportedly went by the name “Dave Kaos,” pleaded guilty in December to multiple charges for his role in the operation, which involved the transportation of what Delahanty called “hundreds of pounds of marijuana” from California to Maine and other states.

In a separate case, a previous Prolman client, former Kennebunk High School hockey coach Donald Hill, was the only one of 68 individuals charged with paying local Zumba fitness instructor Alexis Wright for sex to take his case to a jury trial and win acquittal.

Wright, Thomaston-based business partner Mark Strong and 66 other so-called johns were convicted for their roles in the scandalous case, which attracted worldwide media attention because of its setting in an otherwise quaint Maine town and widespread rumors about whether anyone famous might be revealed as one of Wright’s reported 140-plus clients.