Steven Thomas, the former Mashantucket Pequot treasurer convicted of stealing from the tribe that owns Foxwoods Resort Casino, had turned his life around long before the federal government began investigating the tribe, his attorney said this week in urging that Thomas be spared prison time.

Richard Reeve, in a court filing, said Thomas was “instrumental in changing the culture, priorities and direction of tribal government” and “had a great deal more to give” when theft charges forced him to resign from the tribal council.

Thomas, 39, is to be sentenced Wednesday in U.S. District Court in New Haven.

Elected to the tribal council in 2009, soon after the Mashantuckets’ financial difficulties came to light, Thomas became treasurer in 2012. He stepped down last Oct. 2, a day before pleading guilty to embezzling $177,600 from the tribe — his 2007 salary as assistant director of the tribe’s Department of Natural Resources Protection.

In exchange for his plea, the government dropped two other theft charges and agreed not to oppose Thomas’ bid for a prison term shorter than the 12 to 18 months suggested under federal sentencing guidelines.

Thomas, in court, admitted he “intentionally” signed time cards on which he “overstated” the hours he worked.

In December, the tribe hired him for a position in human resources, according to the court filing.

At the time of Thomas’ indictment in January 2013, the tribal chairman, Rodney Butler, objected to the prosecution, characterizing it as an attack on tribal sovereignty. Federal investigators had begun looking into corruption on the tribe’s reservation in 2010.

“Finally, reasonable people can, have and will continue to respectfully disagree about the value and propriety of this prosecution,” Reeve wrote this week. “… This case appears to be at or near the outer edge of permissible federal intervention in tribal affairs by the institution of criminal charges.”

Reeve described the arc of Thomas’ life as mirroring the rise and fall of the tribe itself. Born into poverty, Thomas’ life “slowly transformed” after his family moved to the Mashantucket reservation in 1986. By the mid-1990s, Reeves wrote, the reservation was rapidly expanding and the tribe’s newly opened casino “was in full swing.”

Thomas, 19 and fresh out of high school, was hired by the tribe’s Natural Resources Department at a starting salary of $45,000.

“That salary grew enormously over a short period of time, and was coupled later with the stipend provided to any tribal member who worked and/or attended school on a full-time basis,” Reeves wrote. “Like the tribe, he made many mistakes, misspent much of the money he was paid and given, and over time developed a false sense of ‘entitlement.’ ”

After defaulting on its long-term debt in 2009, the tribe undertook a massive financial restructuring that was concluded last year.

Thomas “worked tirelessly, honestly and wisely to assist the tribe in extricating itself from its precarious financial predicament,” Reeve wrote. “He helped make many difficult decisions, and advocated, persuaded, pleaded with and convinced other tribal members that the belt-tightening, austerity measures the council was adopting were necessary to right the struggling tribal ship of state.”

Thomas’ older brother Michael also was indicted in January 2013 and was subsequently convicted by a jury of embezzling about $100,000 from the tribe while he was tribal chairman. He began serving an 18-month prison term last month at a federal facility in Massachusetts.

b.hallenbeck@theday.com