These days, Zhang, 37, a third-year University of Pennsylvania Law School student, is career-minded and family-oriented.
But he had a wild side. In his late 20s, he competed professionally as a motorcycle racer.
Further defying stereotypes, he married a woman from Jamaica. Both now are U.S. citizens.
To top all that, when she gave birth to their now-10-month-old daughter, Luna-Soleil, he delivered the baby in their home.
"People like to put people in boxes," Zhang said. "I never squarely fit in one box. I celebrate differences because I enjoy being different. Being out of the mold allowed me to accomplish a lot of different things in my life."
A changing region
"Because Dafan has lived in a lot of different life circumstances and has had a lot of life experiences, he brings that to all of his work," said Amanda Bergson-Shilcock, director of outreach and program evaluation at the Welcoming Center for New Pennsylvanians, an employment and referral service.
Zhang is a member of the center's Friends group. "He has stepped up as one of the leaders of the group, helped to plan events," said Bergson-Shilcock. "His idea of community is really inclusive. As the Philadelphia region becomes more diverse, that kind of inclusive thinking ensures that many perspectives and experiences are at the table."
Zhang, who lives in East Lansdowne, is competing in the May 20 Democratic primary for the 164th state House seat, challenging incumbent state Rep. Margo Davidson.
Davidson, 51, has broken some barriers of her own. She was the first woman, first African-American and first Democrat to be elected to the 164th state House seat.
"He's never run for elected office before, and he's not involved in the party, even in the East Lansdowne party," Davidson said of Zhang. "I think he has a great story. I would like to see him get more involved, but in another way."
Also challenging Davidson in the primary is Billy J. Smith, a lawyer and former Lansdowne Borough councilman.
Zhang sees his political-outsider status as a plus. He also disagrees with Davidson's contention that he hasn't been involved with the local party, saying he helped another candidate campaign in the November election.
Zhang opposes public funding for charter schools; instead he'd like to see all funds directed into the public-school system. Davidson supports public funding for charter schools. Smith, 39, believes that public schools should be "properly funded" before funding other schools.
The 164th District now includes East Lansdowne, Lansdowne, Millbourne, part of Upper Darby and half of Yeadon. According to census data, it is about 47 percent black, 30 percent white, 14 percent Asian and 6 percent Latino.
There is "no clear majority group in the district," Zhang said. The black population in the district is "not all African-American," he noted. There are a "lot of black immigrants."
Back in 2000, the district boundaries varied. It included Drexel Hill, which was mostly white, Davidson said. And it did not include Yeadon or Lansdowne. Then, the racial demographics were 72 percent white, 15 percent black, 10 percent Asian and 2 percent Latino.
Making it on his own
Born in southwest China, Zhang was sent by his middle-class parents at age 15 to attend high school in the Philly suburbs. He came on a visa and had a distant relative in King of Prussia.
He attended Valley Forge Military Academy for a couple of weeks, but didn't like it, he said. He then attended the private Haverford School during part of the 1993-94 school year. His relative rented out an apartment for him in Ardmore.
When school officials found out he was living alone as a minor, they told him he couldn't. Various teachers and schoolmates allowed him to live with them, he said, but eventually the school asked him to leave. Zhang thinks his relative didn't pay the tuition.
"I had nowhere to turn to," he said. "My mom told me that I could just go back to China. My dad encouraged me to try to make a living on my own. It's a once-in-a-lifetime opportunity. I just decided to try to make it, to give it a go."
For much of 1994, he was homeless. He went to New York, where it was hard to find a job, then to Detroit, where he had distant relatives, then to Los Angeles.
Then he came to Philadelphia, where for a month he slept nights in 30th Street Station and at times in unlocked buildings on Penn's campus, he said.
"It wasn't that bad. There were so many people sleeping overnight" in 30th Street, he said. "I was kind of smart. So the cops, whenever they would come and bother you, it was just, 'Do you have a ticket?' 'Cause you can't stay if you don't have a ticket. So I would buy a ticket, and then stay over there and I would return the ticket and buy a later ticket."
He found a job doing prep work for one of the eateries in the Gallery, near 9th and Market streets, and handed out chicken samples.
Then, he got a job delivering food for Chinese restaurants, and had enough money to rent a place in West Philly. "I got hit by a car a couple of times," while delivering the food on a bike, he said. "Nothing bad."
Realizing he didn't want to work in this type of job forever, Zhang obtained his GED in 1995. He also got married that year, but divorced five years later.
After some community college classes, he graduated from West Chester University with a bachelor's degree in computer science in 2010. Meanwhile, he supported himself through computer, Web- and education-related jobs.
After college, Zhang got into Penn's Fels Institute of Government, earning a master's degree in 2011. Afterward, while at Penn Law, he did a research fellowship in Philadelphia City Council, conducting research and drafting memorandums.
It was in the late 1990s when Zhang bought a motorcycle, then started hanging out on Delaware Avenue with other riders, he said. After taking classes at Pocono Raceway and elsewhere, he felt confident.
In 2004 and 2006, he competed in American Motorcyclist Association pro racing events at Daytona International Speedway and at Virginia International Raceway.
"I can't be proven that I can't do something," said Zhang, who had lond hair at the time with tips bleached blond. "So people dare me to do better. If you're going to race, you might as well aim for the top. . . . I decided to do amateur racing, so the goal is to automatically become a professional."
Zhang met his second wife, Sue Ellen, online in 2006. She was a single mother with a daughter, and was working in an accounting office. They married in 2010.
Sue Ellen Zhang, 30, is finishing her undergraduate degree in psychology at Penn's College of Liberal and Professional Studies.
Besides their 10-month-old girl, they have a 4-year-old boy, LiShen, and Sue Ellen's daughter, Teyah Johnson, 12, from a prior relationship.
Their youngest, Luna-Soleil, surprised the couple last year. "I was sitting on the bed and all of a sudden, my water broke," recalled Sue Ellen. "Boo, boo, the baby is coming! The baby is coming!" she screamed to her husband, who was downstairs.
Zhang rushed upstairs and called 9-1-1. He urged his wife to push. After one or two pushes, the baby was out. "By the time the paramedics came, she was already looking at them," Sue Ellen said.
In the fall, the couple co-founded a nonprofit, Education4Tomorrow, which aims to help people get internships, jobs and prepare for college.
Besides finishing his law-school classes, Zhang also serves as an adjunct instructor at Delaware County Community College, where he teaches information technology and paralegal classes.
He and his wife have been going door to door in the 164th District to meet constituents. Sue Ellen is also getting involved in politics, running for a position on the Democratic State Committee.
If he were to win, Zhang would be the first Asian-born immigrant to serve in the state House, according to Tony Barbush, chief clerk of the state House.
Rep. Patty Kim, D-Harrisburg, who is of Asian descent, was born in the U.S., as were previous state House members of Asian descent. The state Senate does not keep records based on genealogy.
Democratic Party insiders in Delaware County think that "there's the black vote and there's the new vote," Zhang said, adding that he doesn't see himself representing any particular group in the 164th District. "I want to represent all. I want to represent people who vote for me and who don't vote for me."
On Twitter: @julieshawphilly