CHRISTOPHER Knaflec wasn't even sure if he was a good person until a reporter asked him what it felt like to be a hero after he'd risked his life to pull a stranger off the SEPTA subway tracks Thursday.

Security footage at the Cecil B. Moore station on the Broad Street Line shows a man walk straight off the platform and onto the tracks about 12:40 p.m.

Knaflec, 32, seated on a bench about 20 feet away, sprang up, ran past stunned bystanders and jumped down to check on the man before yelling to the cashier on the platform to stop the southbound train. Knaflec stayed with the man until help arrived 15 minutes later.

Little about Knaflec's past, though, suggests the pedigree of a subway hero.

He was only in middle school when he was introduced to OxyContin by the older kids in Baden, his depressed hometown of fewer than 5,000 people outside Pittsburgh. By high school, he had moved on to heroin.

Friends and family say he was smarter than he seemed. He studied neuroscience at the University of Pittsburgh for nearly three years, using dope all the while before the habit got the best of him and he dropped out.

He spent the better part of the next 10 years bouncing from house to house, in and out of rehab, until he had exhausted all his favors. His cousin - whom he's so close to that he introduces as his sister - stepped up and took him in to her Toronto home to get him clean.

"I never left his side and he never left mine," said Carrie Felinczak.

Despite her help, he couldn't shake the drugs. He tried staying with his mother in Florida, but relapsed. Back home near Pittsburgh, he checked into a halfway house, and things started looking up before they took another nosedive. Soon, he was spending $300 a day to fuel his habit.

Then his girlfriend told him she was pregnant. His daughter was born in July 2010, despite his recommending an abortion. "I don't remember holding my daughter for the first time," he said.

His turning point came one night a couple weeks later. His baby was crying in her crib, and when he lifted her up, she stopped, looked at him and sighed.

"It was her first, true smile," he said. "That was the most powerful thing I've felt in my life, more powerful than any high from drugs."

That moment helped, but the pressures of his old friends and their old habits were too much. His mother, now a teacher in South Philly, invited him to stay with her.

That was six months ago. On Monday, he got back to Philly after his latest visit to his daughter, two clean years under his belt. On Thursday, SEPTA Police Chief Thomas Nestel said, he saved a man's life.

"I was like 99.9 percent positive that I wouldn't get electrocuted." said Knaflec. "I can't see [the tracks] being able to electrocute you, because too many people would get hurt."

Nestel said at a news conference at SEPTA headquarters that Knaflec's belief wasn't quite right. The track closer to the platform is safe, but the further one carries a deadly current.

"At that time of day, the trains run every seven minutes, and you can see how many people are on the platform," he added, referring to the tape.

Knaflec said he had been heading home from a visit to Temple University, where he was thinking of enrolling to work toward a medical degree. When he reached the fallen man, who officials have identified only as a 63-year-old North Philly native, he cradled the man's neck and back to prevent further injury.

A crush of firefighters arrived about 15 minutes later and took the man to Temple University Hospital.

"He didn't thank me, but I know he was thankful," Knaflec said, explaining that the man seemed to be in too much pain to talk. "You know what I mean? In my heart I believe he was."

Knaflec knows something else: He was the only person at the station that was willing to help.

"With addiction, you really struggle to be you," he said.

He and the rest of his family didn't see the tape of his actions until later, when local news stations put it online.

"I reacted, and that was me. It helps reinforce that I am good. That I am a good person."

Felinczak, his cousin, has a fluctuating number of stray cats in her home near 6th and Federal streets. She said that like those cats, people deserve a second chance.

"A lot of people see people struggling with addiction and they just move to judgment," she said. "But people can change."

On Twitter: @jad_sleiman