WASHINGTON — President Obama, preparing to go behind bars Thursday as part of his push for sweeping criminal-justice reforms, heaped praise Wednesday on a burger chain for hiring an ex-felon.

Obama met with a group of former prisoners this week in advance of his trip to Oklahoma City, where he will visit a medium-security prison and call for reduced sentences for nonviolent crimes, among other reforms.

“I want to give a shout-out to Five Guys, because one of the guys there was an ex-felon, and Five Guys gave him a job,” Obama said at the White House on Wednesday, referencing the burger joint known for its made-to-order burgers and fries.

“And he ended up becoming a manager at the store and was able to completely turn his life around.”

“I tend not to have a lot of sympathy when it comes to violent crime,” Obama continued. “But when it comes to nonviolent drug offenses, [there is] work that we can do to reduce mandatory minimum [sentences], create more diversion programs like drug courts,” and do a “better job” at rehabilitating prisoners, he added.

“This may be an area where we could have some really significant bipartisan legislation,” Obama said, naming Republican senators who back criminal-justice reform.

Obama found an ally in Gov. Cuomo, who told the NAACP convention in Phila­delphia Wednesday that “incarceration madness” is plaguing the nation.

“We have to end this incarceration madness,” he said. “In the state of New York, we spend $50,000 to keep someone in a prison cell.

“You could have sent them to Harvard University for what you’re spending on a prison cell.”