“God granted me freedom so I could help others,” Metrobus driver Sidney Davis said. (Courtland Milloy/THE WASHINGTON POST)

While riding a Metrobus recently, I watched the driver help a blind man find a seat, then help him off the bus, wave oncoming traffic to a halt and escort him — arm in arm — to the other side of the street.

It was a common courtesy made remarkable because the driver was Sidney Davis, whom I’d first met in 1981 when he was an inmate at the Lorton Correctional Complex. He was nine years into a 20-years-to-life sentence for murder.

“God granted me freedom so I could help others,” said Davis, 66, after returning to the bus.

Once considered “incorrigible,” Davis had held the Lorton record for the most time spent in solitary confinement. Then, to the disbelief of many, he declared himself a “born-again Christian” and started an annual prison prayer breakfast and other self-help programs for inmates.

His bus, the U2 from the Anacostia Metro station in Southeast to the Minnesota Avenue Metro station in Northeast, carries scores of schoolchildren in the morning and afternoon. Youngsters in neighborhoods along the route have been known to throw rocks at buses and even spit on, and fight with, bus drivers.

Davis has avoided such trouble. His approach to dealing with kids is to hit them with pop quizzes as soon as they step on the bus.

“Who was the first female mayor of the District?” he asked a teenage girl as she boarded the bus on a recent school day. She didn’t know. “Go back there and ask your friends and tell me when you get off the bus,” he said. The question kept some of the young riders occupied for most of the trip; even some adult passengers got involved by offering clues — in effect, turning the bus into a rolling classroom.

“Sharon Pratt Kelly,” the girl answered with a giggle as she departed the bus.

Davis announced that he wanted to see report cards next time.

Back in 2006, Davis’s unique way of engaging passengers temporarily cost him his job. As the D.C. mayoral campaign heated up that year, he stood in the aisle and spoke favorably about a candidate who’d proposed to do more to help ex-offenders find employment. A story about his endorsement appeared in The Washington Post. Metro officials saw it and fired him.

During arbitration, Davis successfully argued that he’d not been told that making political statements violated Metro rules. Metro officials then claimed that he had lied on his job application by not revealing the felony conviction. But the application only asked if he’d been arrested or convicted in the past 10 years. He had not. He had begun working for Metro in 2003, 11 years after his parole in 1992.

I asked Davis how he had managed to keep his cool during the year-long struggle to get his job back.

“A solid commitment to God,” he said, “to always be about something bigger than myself.”

On Saturday, he’ll participate in a youth summit on violence convened by the Prince George’s County police. This year, 19 people have been shot to death in the county — five of them teenagers.

Davis, a D.C. native, has personal experiences to share. In 1971, during a drug deal gone bad, he was shot and wounded; the other man, shot and killed. He’d serve 20 years for the killing. But the violence was just a symptom. Abusive homes, lack of education, social isolation and undiagnosed mental illness — deal with that, says Davis, and the killing epidemic stops for good.

In Lorton, which closed in 2001, Davis earned a GED and later a bachelor’s degree through the University of the District of Columbia’s prison college program. He also developed relationships with teachers, ministers and other visitors that would form a network of support.

Without that support, his chances of success would have been greatly reduced. About half of the approximately 8,000 people who return to the District from prison each year end up being incarcerated again within three years, according to a 2011 report by the Council for Court Excellence.

Among Davis’s most memorable accomplishments at Lorton was organizing a Special Olympics on the prison yard. Hundreds of disabled children were bused in and teamed up with inmates for a day of races and ballgames.

If a child fell during a race, the inmate chaperon would rush onto the track, pick him up and run to the finish line with the kid in his arms.

“I felt a transformation within myself,” Davis said of the experience. “It gave me a sense of worth, of contributing to society.”

And here he was, more than 20 years after being paroled, still at it — paying special attention to his wheelchair-bound passengers, helping a blind man cross the street.

For previous columns, visit washingtonpost.com/milloy.