Federal prosecutors want former D.C. Council member Michael A. Brown to serve more than three years in prison after a “fondness for money and all that it could buy him” led him to accept thousands of dollars in bribes, they said in court documents filed Thursday.

The memorandum, meant to influence the judge set to sentence him next month, is scathing in its portrayal of Brown as a craven spendthrift, “driven by greed, entitlement, and self-interest” and eager to project “an affluent image commensurate with that of high-profile politicians, lobbyists, and business people” without the financial means to support it.

In a separate filing, Brown’s lawyers asked for a lighter sentence than the 43 months sought by prosecutors and even than the 37-month minimum suggested under federal guidelines. Mercy, they argued, is warranted because of Brown’s cooperation in other federal investigations, his devotion to his family and community and his service as a council member from 2009 to 2013.

“He is remorseful and regrets the pain and disappointment his actions have caused his family, friends, and former constituents,” his lawyers wrote. Dozens of letters urging leniency from Brown’s family and friends, some of them prominent political and business leaders, accompanied the filing.

Brown pleaded guilty last June to accepting $55,000 in cash from undercover FBI agents he thought were businessmen seeking deals with the city government. He was arrested in March 2013 after a sting operation that resulted in photos of Brown taking a coffee mug filled with $100 bills.

As a part of his agreement with prosecutors, Brown agreed to cooperate in the far-reaching federal corruption investigation that led to the guilty plea last month of D.C. businessman Jeffrey E. Thompson. The former contractor’s allegation that Mayor Vincent C. Gray knew about Thompson’s secret, illegal effort to help Gray’s campaign came just weeks before the mayor lost his bid for reelection in this month’s Democratic primary.

But prosecutors said Brown’s cooperation in the Thompson matter did not justify a lighter sentence because he was not wholly forthcoming about his knowledge of the businessman’s corrupt activities.

Brown initially acknowledged in court papers that he took an illegal $20,000 contribution from Thompson during his failed 2007 run for a D.C. Council seat. Months later, Brown admitted accepting more than $100,000 from Thompson to cover vendors’ bills in the final weeks of his council race in the fall of 2008.

The additional acknowledgment added six months to the maximum sentence Brown could receive, from 37 months to 43 months.

Prosecutors said Brown wasted the many advantages afforded him as the son of Ronald H. Brown, the former commerce secretary and Democratic Party leader, choosing instead “to walk a path marred by shortcuts, easy money, and corruption.”

“He had a politically connected and venerated family name, good looks, and a charming personality,” they wrote. “But when it came to the qualities that should matter most for elective office — honesty and integrity — Michael Brown was simply unfit for the political heights he had reached.”

Brown’s financial pressures, the prosecutors said, were rooted in Brown’s desire for “finer amenities and luxuries such as an expensive golf course membership, rent for a high-end apartment, travel, hotel stays, and purchases at high-end retail stores.” He also spent on behalf of others, picking up mortgage payments, food and health care expenses, and tuition costs, they said, while defaulting on his own mortgage and tax obligations.

Together, Brown’s council salary and his income from a series of outside jobs were unable to support his lifestyle. He found other means of support: In a period between July 2011 and May 2012, a relative made payments of $140,000 to Brown’s American Express account.

Brown is scheduled to be sentenced on May 8 by U.S. District Chief Judge Richard W. Roberts.

Among the friends who have written on Brown’s behalf were the Rev. Jesse L. Jackson Sr., BET Networks President Debra L. Lee and Rep. Corrine Brown (D-Fla.), who is not related.

Many of those friends, as well as family, praised Brown for taking close care of his ailing mother, Alma Arrington Brown. “Simply put, Michael is critical to my survival,” she wrote to Roberts this week.

Many of the letters praised his devotion to his twin sons, now in college, who also wrote letters praising their father.

“While our family has tried to keep our lives steady since the news of my dad’s plea, Ryan and I are both having a really tough time,” wrote son Morgan. “I always wanted to be just like my dad. I planned on going to law school and becoming a city council member in DC, just like him. Now I am sad, disappointed and worried.”