Atlanta (CNN) It's 3 o'clock on a Monday afternoon in Clarkston, Georgia, and Dr. Heval Mohamed Kelli is smiling ear to ear.

He looks on as a group of overachieving Clarkston High School students file into a science classroom to receive their after-school lesson for the day.

Kelli rubs his hands in anticipation and then he pauses, if only briefly, to look down.

He stares at his hands, the same hands he used to wash dishes when he arrived to the United States in 2001. Kelli remembers how they would wrinkle like a prune from being under water for too long while working at the first job he had in the US as a Syrian refugee.

"No one ever told me about gloves," he says laughing. "I was washing dishes at nights and weekends to support my parents because my father couldn't work because he was sick."

For years, that's how he supported his family after they arrived in the United States. At 17, he would trek the 6 miles from the Atlanta suburb of Clarkston -- where his family settled in a low-income apartment -- to his job at the Mediterranean Grill just a few miles from where he now stands.

"I would see all the [Emory] students come in to eat and hope to one day be a college student myself," he says. "I always wanted to be a doctor. The prestige of being a doctor was a motivator. That was my American Dream."

In this lesson he leads, Kelli sees himself.

Nearly all of the 15 students are refugees.

Six of them are from Somalia, another from the Ivory Coast. A handful are immigrants from places as diverse as Vietnam and Nepal. Three, like Kelli, are from the Middle East.

Just like the kids who sit in front of him, Kelli, now 33, was a student at Clarkston High, a well-known destination for refugees. That was 15 years ago. Now he's returned as a doctor, determined to give back.

The journey

Kelli remembers his boyhood, when the Syrian government threw his father in jail for months.

"My father is a Kurd and as a civil lawyer at the time he was a prominent person in the community," the physician said. "The Kurds are an oppressed minority in Syria; an ethnic group without a country. So, anyone who has power or acceptance in the local community, the government would be afraid they could start something."

When Kelli's father refused the governments demand to work for them, he was jailed. It took a family friend's influence and money to help get him out of jail.

"After that, his close friend's advised him to leave the country," Kelli says. "He went from being a lawyer to fighting heart disease and depression after what he went through. He was so prominent, and now in America he can't practice."

The family first made their way to Germany.

Two weeks after September 11, 2001, Heval Kelli arrived in the United States.

It was a strange time to be a Muslim, but the 17-year-old felt American almost from the moment he stepped foot in the country.

"I remember at the airport in New York, a man came up to me and started showing me pictures of his dog," Kelli told CNN. "It was amazing. I didn't speak English, but this guy thought I did. He thought that I was American. It was an incredible feeling."

Eventually, Kelli, his younger brother and his parents resettled in Clarkston.

Life was a struggle.

In the months that followed, the student would wash dishes, hoping to make enough money to not only support his family, but also one day send himself to medical school.

But it was only just a dream.

"It was hard to think about becoming a doctor when you're learning English and struggling as a refugee," he says. "I wished then that I had a mentor to motivate me," he added.

"Living in Clarkston, in poor neighborhoods, your neighbors are not doctors and engineers and lawyers. So you lack that role model and the motivation."

Kelli's vision may have stayed only a dream if it wasn't for an act of serendipity. Kelli's younger brother, who had obtained an academic scholarship at a private high school in Atlanta, mentioned to a classmate that his older brother wanted to be a doctor. As chance would have it, the classmate's father was a heart surgeon and Emory School of Medicine professor.

It was the mentor Kelli needed to make the push to become a future doctor. More than a decade later, Kelli is a cardiology fellow at Emory University.

"The restaurant [where I used to wash dishes] is one block away from where I train as a cardiology fellow today," he says.

But perhaps even more unimaginable for Kelli, is coming back to Clarkston High as a doctor and, more importantly, as a mentor.

The need to invest

"Intelligence is relative, but everyone can be a hard worker," Kelli says to one of the students in the monthly session.

The group is part of the Young Physicians Initiative , or YPI, an after-school program Kelli started in the fall at his former high school.

Years ago, he noticed first-hand the void of mentors in Clarkston, so he began the program to give back. The goal is to inspire others like him to pursue a career in medicine.

"I feel the obligation as a physician that my service goes beyond patient care: I need to invest in the community," he says. "So we started the Young Physicians Initiative as a way to re-create my story in Clarkston."

He partnered with Emory University and recruited his medical students to start a premedical education program for high schoolers.

"I thought that I had it hard, but these kids struggle with having two jobs, taking care of their sick parents, and (they) are still motivated to become a doctor."

Students like 18-year-old high school senior Christopher Keke, who works at a day care to support his family, while also going to school and attending the YPI after-school program.

"Being the first generation going to college, I would say that it's very important," Keke, whose family immigrated as refugees from West Africa, told CNN. "I have no option. I'm doing it for my family, and also for myself for a better living. I want to give back, not just to my community, but for my parents for all the suffering and hard work they've done. I want to show them that it wasn't for nothing."

He says: "I just want to change the world."

Kelli believes that Keke and the others in the YPI program will one day change the world. In fact, they've already changed his, as he has theirs.

Kelli does what he does, in part, to honor the legacy of his father.

"I always tell people this country is great," Kelli says. "The greatness of this country is our interactions and diversity. If I, as a refugee, could come here and become a physician 15 years later across from the restaurant where I used to wash dishes ... this is the American Dream, and everyone could do that."