In an interview, he pondered life behind bars: his friendship with an ex-gang leader from Philadelphia, the routine of walking the yard, and his newfound compassion for lawbreakers.
As a legislator, DeWeese was known to immerse himself in a subject for a year - African American history, Israel, or the Civil War. More recently, his focus has been the criminal justice system - from the inside.
A goal after his release is to get involved in prison reform, an effort DeWeese, 63, said could be aided by other lawmakers and staffers who have served time.
"If all of us put our heads together, we could save the state a lot of money," he said.
His portrait hangs prominently off the Capitol Rotunda with other House speakers of the past, just down the hallway from Benjamin Franklin.
But since 2012, DeWeese has been just one of 1,200 inmates in rust-colored jumpsuits and white slippers at SCI Retreat, a medium-security prison southwest of Wilkes-Barre. On Sunday, he's expected to cross the bridge over the Susquehanna River that separates the prison from the hardscrabble old coal-mining community and return to his home in the southwestern corner of the state to begin his three-year parole.
Convicted of misusing $125,000 in taxpayer money to pay staff members to do campaign work on government time, he was sentenced to 2½ to five years in prison.
DeWeese has long maintained his innocence. In the interview, he declined to discuss the case, saying he might take an appeal to federal court. (The Pennsylvania Supreme Court last fall denied his post-conviction appeal on due-process grounds.)
He won early release thanks to a 2008 law he voted for that allows nonviolent offenders who meet certain conditions to serve 75 percent of their minimum sentence.
An anonymous blog post he saw shortly after arriving for evaluation at Camp Hill prison near Harrisburg in May 2012 set the tone for his time behind bars. It said he would fare well in prison because he'd see it as "a grand adventure."
He said he thought, "That's exactly what I am going to do."
By the time he arrived at SCI Retreat, he said, the prison was abuzz.
"They knew I was coming," DeWeese said. "They said, 'You're the crooked congressman.' " (Even though he never served in Congress.)
DeWeese, a Waynesburg resident who was so popular in his Greene County district he was elected even after his conviction, found himself cultivating new constituents - only none of them could vote.
In the visiting-room interview, DeWeese called to the prison trusty taking snapshots of inmates and their families in front a cloth backdrop with an image of a bucolic waterfall.
"Am I the happiest guy in this place?" he shouted.
"You know it, Governor," the trusty replied, using one of the ex-speaker's other nicknames.
DeWeese laughed and carefully arranged his Cheetos on a napkin while Sesame Street played on a TV across the room in a small play area with toys for inmates' children.
"They say, 'In one or two years, even Mama forgets lifers,' " he said, surveying the room, where a half-dozen inmates huddled with girlfriends. "The best thing they have other than their freedom is a visit."
DeWeese said he spent his days watching C-Span, writing letters, lifting weights, chatting with a steady stream of visitors - some of them sitting lawmakers.
When the weather was good, he "walked the yard," as he likes to say, below Homicide Hill, so named for the convicted murderers who gather there.
DeWeese was the only recently convicted politician sent to a medium-security prison, one with murderers, rapists, and child molesters, like his 74-year-old cellmate.
A corrections spokesman, Sue Bensinger, did not explain why, saying only, "Inmates are sent to the appropriate facility based on programming needs and open bed space."
DeWeese said his Marine Corps service 40 years ago helped steel him for life on the cell block - the yelling, the lineups. "It's not as intense as the Marine Corps," he said.
He said he visited prisons - two of the largest are in his old district - during his time in the legislature, but thought little about those who lived there. Former inmates likely wouldn't have crossed the marble transom of his Capitol office.
His best friend on B block, he, said was a Muslim from Philadelphia, Kevin "Amir" Bowman, a former gang leader convicted in a notorious drug-related murder in 1990, who he said taught him the finer points of weightlifting.
"The pathway for the last two years has been one of immeasurable growth and education and appreciation for a lot of folks who heretofore I wouldn't have come in contact with," DeWeese said.
Former Republican lawmaker Jeff Coleman, a friend and frequent visitor, said prison had been a transformative experience for DeWeese, who long held a position of privilege and power.
"It's certainly tough on his family, his mother, and siblings," he said. "It's a debasing experience but gives you a real opportunity to do self-examination."
DeWeese said he hoped to return to Harrisburg one day, though he's not sure what he wants to do.
Not all of his old colleagues will welcome him with open arms.
Several who were interviewed and were reluctant to speak publicly said DeWeese represented the culture that for too long blurred lines between legislating and campaigning and thought he threw his staff under the bus to protect himself.
DeWeese said he was not sure he wanted to tackle prison reform in the evangelical style of Watergate felon Charles Colson. But he said he'd like to share his experience, find ways to keep nonviolent offenders out of jail, and make life more humane for those who do end up behind bars.
It troubles him, he said, that his facility axed many of its vocational programs, including most recently the greenhouse, which helped inmates land jobs upon release.
Corrections Secretary John Wetzel said in an interview that maintaining the greenhouse was too expensive and that the agency was transitioning Retreat to a facility to serve inmates with mental-health issues.
For a man who has spent his working life in politics, DeWeese said it was a strange feeling not knowing what direction his life will take next.
"I knew what I wanted to do from the moment I saw John F. Kennedy get elected," he said. "I think I can make a contribution and offer something that is of benefit to Pennsylvania."