"Thank you," one man, a Vietnam veteran, whispered to Johnson after the two made plans to speak by phone later that day about the man's troubles.
At one point, he gestured toward a grassy park where a woman and child played.
"I slept here a couple of times," he said. "A lot of the guys I run into, I got high with when I was homeless."
That's because Johnson, 41, wasn't always the one doing the helping. Last time he was here, he was one of the lost.
Wrecked after a stint in Iraq, he spent a best-forgotten year addicted to crack and sleeping on the same streets he walks today.
Now he's back, determined that no other veteran will suffer as he did.
"We want vets to know there's support here," Johnson said. "We're not going anywhere. We're engraved in stone now."
'The lowest low'
Johnson, 41, was born and raised in Chester. He joined the Army at 19. His was a fulfilling, but uneventful, stint until he was deployed to Iraq in 2004. He was based outside Baghdad in a camp nicknamed "Mortaritaville" because of the daily bombings it received. He was also part of a medical team that handled triage.
That's pretty much all Johnson will say about his time overseas. Ask questions and he'll just shake his head and look away. He won't go into many details about what he did or what he saw.
"I don't like to go there," he said.
He returned home to Chester in November 2005. By his own account, he spent much of 2006 drunk or high. Crack was his drug of choice.
His mother threw him out of their house. He doesn't blame her for that.
"No one wants to deal with you when you're smoking crack," he said. "My mom was scared of me. She changed the locks."
His mother, Betty Johnson, said that she did change her locks every two months, though it hurt her to see her only child this way.
"As a mother, your heart is out there when he's out there," she said. "You don't know where he is or what he's doing.
"God took him to the lowest low."
To support his habit, Johnson ran errands for his drug dealer. He was picked up by police for loitering. He slept in empty buildings or the woods or open parks, or spent all night walking through the city. He attempted suicide by overdose.
"I don't remember much of 2006," Johnson said.
One day, he just had enough. He went back to his mother's home. He asked her to take him to the Department of Veterans Affairs Hospital near Baltimore.
"He just came to me and said, 'I'm tired,' " his mother said. "He brought himself in and did what he had to do to get clean and sober."
Johnson spent a year in the VA hospital system, battling his addictions. There, he was also diagnosed with chronic post-traumatic stress disorder.
While he was struggling in the hospital, he had an idea for an organization that would help veterans like himself.
"I probably would have gotten off the street sooner if there was a veterans' organization in the city," he said.
'A great motivator'
In the VA hospital outside Baltimore, Johnson remembers watching fellow patients line up for the daily drug dispensings and feeling their stress choking him.
Wali Mutazammil, Johnson's roommate in Baltimore and a Heroes Today board member, discussed the concept of the nonprofit with Johnson.
"It's very personal," said Mutazammil, a Vietnam veteran. "We're here to embrace you and be with you for as long as it takes, even the rest of your life."
After a year in the VA system, including a transfer to the Pittsburgh VA, Johnson was released in 2007. He started to make his concept a reality in that city.
Although the focus was homeless veterans, he wanted to offer aid to any veteran. He organized regular dinners sponsored by area restaurants, connected with legal-aid associations and joined forces with other veterans-assistance organizations.
Johnson's gift is his ability to network, and he managed to get so far with money provided by only himself and his board members.
"He helped a lot of guys get their things straight and in order," said Scott Havelka, secretary of the Pittsburgh chapter of the Military Order of the Purple Heart, a veterans-assistance association. "He's a great motivator."
Mutazammil easily listed a few of Heroes Today's Pittsburgh accomplishments, including finding homes for the homeless and securing cheap cars for those who needed them.
"We know that we're making a difference," he said. "We're still pretty much doing this out of our own hip pocket, but we don't even think about that. We just do it."
With the Pittsburgh organization established, Johnson brought Heroes Today to Chester.
'A giving heart'
Johnson is one of Chester's biggest supporters, calling it patriotic to the core. Johnson estimates that about 3,000 veterans call the city home.
But it needs more veteran-support services, he said.
"Vets, once they identify someone else is a vet, they have something to talk about," Johnson said. "Veterans serving veterans' organizations are the most effective. A lot of veterans are so proud, they won't reach out to strangers for help. Some here have been jerked around so much, they're just tired of it."
So, Johnson does his guerrilla marketing, walking the streets, sticking fliers everywhere he can. He's starting a peer-to-peer support group. He'd like to find a permanent office space.
Earlier this month, Johnson organized his first major event: A job and health fair held at Chester's City Hall. More than 100 veterans - and some nonveterans - visited the fair, which included 15 potential employers, five colleges and representatives from different VA departments.
Betty Johnson said she was leery when she heard that her son would be moving home. But then she saw the transformation he had undergone.
"Once I saw he was so determined, I knew it was going to happen," she said. "He has a giving heart. He's always had a giving heart."
And he's committed to his cause.
"He lives, eats, breathes, sleeps Heroes Today," said Kim Jennings, a Chester resident who has joined Heroes Today's Veterans Outreach Committee. "That's all he talks about. It's not an organization that hears your problems and says, 'OK, we'll see what we can do' and leave it at that. It's made up of a bunch of people who are really go-getters."
For his part, Johnson is certain that he's finally on the right path.
"I would never have imagined myself giving so much of myself without getting anything in return every single day," he said. "It's the motivation to help others that keeps me going."
For more information on Heroes Today, go to http://heroestoday.org or call 888-386-9445.