She's kicked off a whirlwind book tour, but set aside a few minutes to talk to ABC7 News.
There was warm welcome for the former first daughter at Everett Middle School.
With a family of her own, Clinton is all grown up, but America still remembers when she was in middle school.
"I was this age when I was living in the White House," she said.
She was quite the reader back then.
"And I read this book that had a big impact on me called '50 Simple Things Kids Can Do to Save the Earth,'" she said.
Teaching kids they can help the environment inspired Clinton to write her book about other global issues and kids helping to solve them.
"Hi, my name is Theo, and I read the part about poverty around the world," he said.
The kids did their homework.
"How can we get adults to really take us seriously?" another student asked.
And in true Clinton fashion, Chelsea answered by telling stories.
"When I was 5, I wrote this letter to President Reagan," Clinton said to students.
Looking out at the audience, she saw a room full of hope.
"Their questions, their ideas, what they're doing, this is exactly why I wrote 'It's Your World,' because I know there are so many kids who are interested in changing the world, and just want to know what more they can be doing," Clinton said.
San Francisco marks the start of the second leg of Clinton's cross-country book tour, visiting not only schools but also some of the nonprofits she wrote about.
At micro-lending nonprofit Kiva, Clinton heard from kids who are making a difference for entrepreneurs in developing countries.
"It makes us feel good to give someone the opportunity to thrive," said one boy.
For these kids, Clinton's message just makes sense.
"Even though I'm young, I can change people's lives even though they're on the other side of the world," said Connor Chen.
Back at Everett Middle School, student elections are Friday. Clinton calls that good practice for future leaders.
"Because I don't think anyone should ever rule out politics as a way to make a difference," Clinton said.