A disgraced Atlanta charter school founder who a prosecutor said caused losses of at least $1.2 million by actions including stealing money he spent on strip clubs and luxury cars, admitted guilt Tuesday and apologized.

“I am deeply thoroughly overwhelmingly sorry. I am responsible for what has happened. I take responsibility for my actions, and I know that I allowed my own unchecked ego to lead me on a ludicrous adventure that led to absurd results that left a lot of people hurt,” Christopher Clemons told a Fulton County Superior Court judge on Tuesday.

Clemons pleaded guilty to 55 theft and forgery counts in two criminal cases linked to troubles from three charter schools he helped found. One of them, Latin Academy Charter School, was forced to close because of the financial mess he left it in.

Judge Thomas Cox gave Clemons, 39, a 20-year sentence and ordered him to pay restitution of $810,000. Clemons is to serve 10 years in prison, with credit for the roughly 21 months he’s been in jail awaiting the conclusion of his cases, and 10 years on probation.

The guilty plea punctuates a dramatic fall from grace for Clemons, an Ivy League graduate of the University of Pennsylvania with an MBA from Massachusetts Institute of Technology.

Just a few years ago, he was heralded as a charter-school champion. But soon after he helped launch Latin Academy, a middle school on the city’s west side whose charter was authorized by Atlanta Public Schools and where he served as principal, he began stealing from it, said Fulton County deputy district attorney Brad Malkin, of the white collar crime unit.

Malkin traced the start of the thefts and misappropriations to 2011 and said the problems would continue for another four years at Latin Academy, undetected by the school’s independent board. Clemons was responsible for the school’s finances, Malkin said.

Before he was caught, there would be time for Clemons to wreak havoc at two other charter schools, Latin Grammar School and Latin College Preparatory School, which he founded under authorization from Fulton County Schools. Both of those schools are still open.

“The damage that Mr. Clemons did was enormous. He stole over and over again,” Malkin told the judge. “Not only did it disrupt lives of children, but also their families. It caused good people to lose their jobs. It caused a school to lose its charter and embarrassed the Atlanta Public Schools system. And it was a totally selfish act at the expense of many innocent people.”

The thefts came to light after a new principal at Latin Academy examined bank statements and spotted suspicious charges, cash withdrawals, and transfers.

In court, Malkin detailed a few of the egregious examples investigators found, such as $50,000 spent at strip clubs and in cash withdrawals at strip clubs over dozens of visits. Malkin said Clemons signed a credit card receipt for $12,000 to cover just one of those excursions.

The strip-club expenses were coded in school records as expenses related to staff development, entertainment, or recruitment, Malkin said.

Clemons also improperly wrote checks to pay off two BMW vehicles, wired tens of thousands of dollars to his personal account, and withdrew cash — many times on weekends or school holidays — from Latin Academy’s accounts, Malkin said.

Latin Academy was in financial trouble when its independent board decided to close the school in 2016, though the Atlanta school district already had said it planned to terminate the academy’s charter.

Prosecutors contend Clemons, without authorization, put money provided to the other two charter schools by the Fulton County Board of Education into a bank account of his Latin Schools Foundation. He also improperly entered into agreements for short-term loans and an equipment lease, according to court documents.

Judge Cox repeatedly questioned Malkin about what financial controls were in place at the schools and the role of board oversight. Malkin said leaders were not suspicious based on the information they reviewed, and said such cases often involve a person who is “well trusted” and “well respected.”

Kaseem Ladipo, the former Latin Academy board chairman, told the court in a victim statement that the thefts led to distraught parents and a community that no longer trusted the adults.

“It’s sad, no matter how you look at it. No one is leaving here with smiles,” he said, after the sentencing.

Clemons left Atlanta during the investigation. He was arrested in Denver in April of 2016 and extradited nearly four months later to Georgia, where he has remained jailed.

Clemons, wearing a navy, jail-issued top, was contrite when he addressed the court Tuesday.

“It’s mind-boggling to me, and all I’m left with is just the stark reality of the damage that I’ve caused and the incalculable horror of realizing that I systematically worked to deprive children of the opportunities that allowed me to get to the place that I am now,” he said.

He acknowledged the anger of the victims, the public and Georgia taxpayers and said he shares that anger and shame for himself.

Clemons, who previously has said he helped start more than 30 schools across the country, said learned humility while in jail and promised to “make something useful” out the rest of his life.

“It’s taught me that the reward for doing good is doing good itself. There’s no other reward that you are entitled to that’s beyond that,” he said.

Among the additional conditions he received at sentencing, Clemons is not to consult with any school district, work for any nonprofit, or work with children.