Hours after the sniper stopped shooting in Texas, Bob Faherty was still struggling to figure out how peace officers with badges on their chest and guns on their hips could be ambushed on the streets of Dallas.

“I can’t make sense of it,’’ said Faherty who spent most of his career keeping the peace on the darkened streets of Boston, rising to become the city’s second most powerful cop. “It’s tough to be a police officer today. I wouldn’t want to be a police officer today.’’

There’s power and poignancy behind those words when you consider who Bob Faherty was when he wore the uniform of the Boston Police Department and what he has devoted himself to in the years since he retired in 2000.

He spent 40 years on the force, beginning in Roxbury where he walked a beat in the days before walkie-talkies and checked in with headquarters by street-corner callboxes every 40 minutes or so.

“You’re out in the fresh air, you’re meeting people,’’ he said. “You get to know people.’’

Along the way, Faherty built a gold-plated reputation as a working cop who used a blend of compassion, wisdom, and toughness to defuse volatile confrontations on the street. He had no time or leniency for rogue cops who would stain the reputation of the good ones.

He led the city’s gang unit when Boston’s homicide rate was startlingly high and he worked until it was halved over a two-year period. He delivered babies, looked into the eyes of women whose husbands had been killed on the job, and drove himself around town when he had risen to a position that came with a car and driver.

And when it was over, he didn’t want to leave.

“I loved the job,’’ Faherty told me on the telephone from Falmouth on Friday. “They had to kick me out the door when I turned 65. I stayed until 6:30 or 7 o’clock that last day. I’d probably still be on the job if they didn’t have an age limit.’’

And, yet, in a way, the retired superintendent in chief found a way to keep doing what he most loved about police work: helping people.

Faherty became chairman of a nonprofit called Cops for Kids with Cancer, which was founded in 2002 by John Dow, a retired Boston police commander who died of lung cancer in 2007.

The group’s mission statement is as remarkable and simple as its effect is profound. Your kid has cancer? Here’s $5,000.

“When the word got out that we were giving out $5,000 people would call me and I would tell them to go to their local police department and have the police department call me,’’ Faherty said. “If they were phonies, they never went to the local police department.’’

But those in need did. People like the parents of an 8-year-old Springfield girl who lost her leg to cancer and then asked if she could keep its cremated remains on a shelf at home.

Or the parents of a 3-year-old Watertown child who was diagnosed with cancer last fall and needed help to pay for treatment and to make up for lost wages.

The money comes from charity runs, golf tournaments, and comedy nights. Something new nearly every month.

“The hardest thing to do is to raise money when you’re not Tom Brady or Big Papi,’’ said Faherty. “You’re always hustling.’’

Since 2008, Cops for Kids with Cancer, where no one draws a salary, has raised more than $2.2 million and assisted 458 families.

“Everyone has a different story,’’ he said. “And that’s what kept me going.’’

Until last month. Bob Faherty, 81, retired from the group in June.

The organization is in good shape. Its board is strong. Faherty plans to assist in any way. But this time, he’s really retiring.

People who know him best say his 40-year record with the Boston Police Department and the work he’s done since to help sick children and their families is the truest emblem of what it means to protect and serve.

He makes no excuses for the inexcusable. Police work is tough, exacting, and exhausting work. It also requires — demands — integrity.

He upheld those standards on the streets of Boston for 40 years. It’s why he was so universally respected even before he spent all those years raising money for sick kids and their families.

It’s why he is now struggling to understand how so many cops could be used as target practice and how so much police work is ending in inexplicable bloodshed

Thomas Farragher is a Globe columnist. He can be reached at thomas.farragher@globe.com.