Behind Los Altos High School’s fan-favorite Fashion Design course is Yoonsun Chai — the teacher and creator of the class. For Chai, it’s part of her lifelong dream come true. 

Chai knew she wanted to pursue fashion early in life — growing up in South Korea, Chai was inspired by her father, who owned a leather coat manufacturing company. Her father’s involvement in clothing production led Chai down a similar path.

Her first step to a career in fashion was in high school. She studied design at Sunhwa Arts School, a prestigious arts high school in Seoul, South Korea.

“In fine arts, you have to create from nothing, but I like to work with things that already exist and make them into something better,” Chai said. “Fashion design is exactly that.”

At 18 years old, freshly graduated from high school, she moved to New York to study at Parsons School of Design, a private art and design college. At Parsons, she met new people from all over the world. One of these people was Shu Tu, a fellow first-year student from Taiwan.

“We both had just come from Asia and didn’t speak perfect English,” Tu said. “But Yoonsun had this infectious laugh, and it was always so easy to be around her. Even when we couldn’t communicate well, it was wonderful being with her.”

At Parsons, Chai stood out as one of the top students.

Unfortunately, Chai’s fashion journey came to a halt when her father’s company suffered an accidental fire. Her family struggled financially, and Chai could no longer afford to continue studying at Parsons. So, she transferred to the Fashion Institute of Technology (FIT), a public college in New York.

“She’s such a resilient person,” Tu said. “When she transferred to FIT, she had to become an adult overnight. Yoonsun knew she wanted to do fashion from an early age, so even as challenges came up, she kept pushing through and being very positive through it all.”

As Chai studied at FIT, she interned for brands such as Perry Ellis and Donna Karan, transitioning to working full-time by her third year. Her dream?

“I really wanted to work for a big company, so I put my portfolio online just in case,” Chai said. “I was an international student, so companies would have to sponsor me if they wanted to hire me.” 

But to Chai’s surprise, Macy’s contacted her for an interview. There, the senior manager simply looked through Chai’s portfolio and was so impressed that she told Chai to design something for her at home.

“I told her that I was an international student and I needed a visa,” Chai said, “She then told me, ‘It doesn’t matter. If I want somebody for a job, I can get them in.’”

Her willingness to push herself wasn’t new; it was the same work ethic she’d shown while still at school.

“Back then, knowing Photoshop or Illustrator was rare,” Tu said. “She taught herself how to use it because she knew it would make her a better designer.”

With her visa and job secured, Chai began working as a designer for Alfani Intimates, under Macy’s, in 2005. Her work took her from Asia to Europe.

“A large part of my job at Macy’s was to go shopping,” Chai said. “My design team had to read trends and get samples for our designs. As a young girl, it was really fun — free travel and shopping.”

In the six years Chai worked at Macy’s, she met her husband, who worked in Macy’s retail technology department. After having two children, Chai became a freelance designer for eight years. Around this time, she moved to California for her husband’s job. There, she began her teaching career.

First, it was small art classes. After her neighbors and friends heard about her background, they asked her to teach their children art. Chai agreed, and before long, her class size grew from just 4 kids to 25.

Then, Chai started teaching high schoolers.

“One day, my friend asked me about teaching at high school,” Chai said. “At the time, I was studying art therapy. I thought that being a school teacher would allow me to understand teenagers better.”

After joining LAHS as an art teacher in 2019, she has been sharing her experience in the arts and the fashion industry through her classes. Chai teaches Drawing I and Fashion Design I, and will be teaching Fashion Design II in 2026.

“Some of her assignments were so design-heavy in the best way,” CTE specialist Amber Woodward said. “As a former art teacher myself, I could tell right away that the level of detail in her assignments came from a teacher with real industry experience.”

Today, Chai leads the school’s Fashion Design pathway, blending her industry experience with her passion for teaching. 

“She is an excellent teacher,” Woodward said. “Her background, her thoughtfulness and her care for student learning really make this class the perfect pathway for her. And it’s only going to grow from here.”