Priscilla Chan remembers seeing blood all over the boy’s face, a sign he had gotten jumped in his own neighborhood. For the first time, just looking at someone else hurt.

Chan, then a Harvard student and now a Bay Area philanthropist, pediatrician, mother and wife of Facebook co-founder Mark Zuckerberg, was mentoring the child in an after-school program meant to quell gang violence in Boston’s Dorchester neighborhood. Yet stellar tutoring and field trips to football fields and skating rinks couldn’t cure the student’s woes.

“I realized that my homework help was going to completely be futile if these kids couldn’t be healthy, safe and happy in the place that they lived,” a teary-eyed Chan told this newspaper in a rare interview. “That really drives a lot of what I decided to do in my life and career.”

Chan is the private face of the philanthropic couple, working quietly behind the scenes. While Zuckerberg is a prominent player among Silicon Valley’s tech elite and his life story is widely known, Chan rarely talks publicly about how her personal story has helped shaped the couple’s multimillion-dollar donations to schools and hospitals.

Wealth and power used to be foreign to Chan, the child of immigrant parents who fled Vietnam on refugee boats in the 1970s and never went to college.

Now Chan and her husband have invested hundreds of millions of dollars to improve education and health care for children, including in the Bay Area. They have vowed to donate 99 percent of their Facebook’s shares — worth more than $45 billion — to charitable causes.

And Chan, a former teacher, has taken it a step further. In October she announced she was founding and would be CEO of The Primary School, which will link health care and education for 50 families from East Palo Alto and Menlo Park’s Belle Haven neighborhood when it opens this fall. Teaming up with the Ravenswood Family Health Center, the free school, serving students from pre-K to eighth grade, will provide services from mental health to prenatal care for students and their families. The private school is funded by Chan and Zuckerberg, but they have not disclosed how much they are pumping into the effort.

Suddenly Chan, a San Francisco General pediatrician who has largely shied away from public attention, found herself in the spotlight as the doctor spearheading change for some of the Bay Area’s most disadvantaged children.

It wasn’t one defining moment, but rather a series of experiences, that would lead Chan on a journey back to education, to a place between the classroom and doctor’s office.

While Chan was growing up in Quincy, Massachusetts, her family stressed the importance of school and hard work as the keys to a life better than the one the Chinese-Vietnamese refugees left behind.

But even in a place nicknamed the “Birthplace of the American Dream,” Chan knew her upbringing was different from those of other children raised in the Irish Catholic town.

“My identity, I felt, was so distinct. I felt very much like an outsider. My family didn’t have the same rituals that everyone else seemed to have,” she said.

Her Cantonese-speaking grandparents raised her and two younger sisters while her parents, Dennis and Yvonne, worked long hours at a Chinese restaurant and other jobs.

And while her parents never attended college, they wanted their daughters to do better, though it was an abstract idea rather than a road map filled with a list of specific colleges and test scores. Once, Chan told her mom she wanted to take the SATs. “What’s that?” her mom asked.

At Quincy High School, Chan’s teachers helped fill in the gaps.

Peter Swanson, her science teacher and tennis coach, remembered Chan asking if joining the tennis team could help get her into a college like Harvard. It wouldn’t hurt, he told her, along with straight A’s, advanced courses and high SAT scores. Voted “class genius,” Chan wasn’t a naturally gifted tennis player but worked hard to improve her reflexes on the court.

She became the captain of the tennis and robotics teams and graduated at the top of her class in 2003. Sure enough, Chan got accepted to Harvard early. “Teachers can inspire students, but students can inspire teachers,” Swanson said. “She was an inspiration.”

In her valedictorian speech, Chan quoted Dr. Seuss’ “Oh, the Places You’ll Go!” She shared lessons she learned from traveling to Europe, China, Korea and Hong Kong with her grandmother, who she called “Mama.”

“Mama showed me that I didn’t have to change just because someone else saw things differently,” she told her classmates. “She showed me that having differences is normal and that I didn’t have to be afraid of the differences in all of us.”

At Harvard, surrounded by brick buildings, libraries and bronze sculptures, Chan saw the wealth of opportunities an Ivy League education could bring, the doors it could swing wide open.

But Chan felt out of place — even more than she did growing up Asian-American in Quincy. She felt as though she had gotten to the college by chance. Doubt crept into her mind, but so did the desire to give back.

“These opportunities for sure were not available to many of the people I grew up with,” Chan said.

So she went to the Phillips Brooks House Association, a student-run nonprofit at Harvard, and signed up for the Franklin Afterschool Enrichment program. Volunteers met at the front of Lamont Library, taking buses to the Franklin Hill and Franklin Field public housing units in Dorchester, where they tutored and mentored children. Initially a summer youth program for the children of Harvard University’s dining hall workers in the 1980s, it later expanded to serve the housing projects after a surge of gang violence in the 1990s.

Seeing a kid with blood on his face because he got jumped was the first time Chan felt visceral pain for someone else, but it wouldn’t be the last. She remembered searching for a girl who had missed days of school. When Chan found her in a park, she noticed the child’s front teeth were missing, another memory that brought tears to her eyes.

It was at Harvard that Chan met Zuckerberg while waiting in line for the bathroom at a fraternity party. The couple married in 2012 in the backyard of their Palo Alto home in a wedding disguised as a graduation party.

After earning her biology degree from Harvard in 2007, Chan spent a school year teaching fourth- and fifth-grade science at The Harker School, a private college preparatory school in San Jose.

“Those kids were completely different than the kids that I taught in the after-school program,” said Chan, who will be the keynote speaker at Harker’s graduation this year. “But kids, in general, have common grounds and common foundations that they need to build.”

At the end of the day, she said, teachers want to see all their students grow into happy, productive adults who have a passion for what they’re doing.

Harker students knew that her boyfriend was the Facebook CEO, but none of them really cared, said Naomi Molin, one of Chan’s students. The class built a roller coaster out of K’Nex pieces to learn about physics. During recess, Molin and her friends would run up to their favorite teacher, cling to her legs and refuse to let go. “She was one of the easiest teachers to talk to as a student,” Molin said.

In 2010, Zuckerberg and Chan embarked on their first major education project, donating $100 million to turn around public schools in Newark, New Jersey. But the work was characterized as a failure, a top-down education reform effort with large chunks of the money going to labor and contract costs, charter schools and consultants.

While Chan and Zuckerberg have acknowledged that trying to improve New Jersey’s schools came with challenges, they’ve also said it produced higher graduation rates and taught them the importance of working with the community.

The path from child to adult is a long and winding road, and Chan knows she can’t do the work alone. There’s no antibiotic, no medicine the doctor can prescribe to cure domestic violence or other issues a kid may encounter at home. The Primary School’s team, she said, spent a year learning about the surrounding community.

At a recent community roundtable that included U.S. Secretary of Education John King Jr., the conversation between The Primary School and community members continued. Chan heard from school leaders in the area concerned about the gaps in special education funding, parents frustrated by disorders such as depression and autism, and a student who yearned for more engaging classes.

East Palo Alto, a disadvantaged, racially diverse city of about 29,000 people, stands out among the wealthy and educated tech enclaves of Silicon Valley. Only a small percentage of students go on to earn a bachelor’s degree, and 16.6 percent of the city’s residents are living in poverty. Much like the low-income housing units that Chan worked in during college, the city has a history of gang violence and in 1992 had the nation’s highest murder rate. Since then, East Palo Alto has become safer, with violent crimes dropping 64 percent from 2013 to 2014, a federal crime report shows.

Inspired by working with kids in the after-school program and as a pediatrician, Chan started quietly working on The Primary School while she was a resident at UCSF. As part of the Pediatric Leadership for the Underserved program, residents had to complete a project, but Chan had her sights on a task that was far more ambitious — opening a new school.

“It was incredible what she pulled off. Being a resident and working that sort of arduous schedule is taxing in and of itself,” said Dr. Meg McNamara, a mentor in the program who worked with Chan. McNamara said Chan has a knack for seeing the big picture but keeping an eye on the details — understanding the larger impact of a child’s life outside of the doctor’s office.

In an office space already filled with bursts of bright colors, The Primary School’s logo — a hand with a heart in its palm — jumps out. Incorporated into the logo are images that represent the school’s five values: excellence, growth, courage, community and soul.

Chan, who gave birth to her first child — a daughter — in late 2015, knows education reform can’t wait.

“Before I had Max, I had all these experiences that gave me what I felt like was a strong empathy for how important it is for children to have all these opportunities and how much families want to invest and want the best for their kids,” Chan said. “But after I had Max, I feel that every day.”