Walden School's Administrators oversee the daily operations of the school, providing an important and valuable link between the faculty, staff, parents, students, and community at large.


Hariani Laksana

This is my 18th year at Walden. I received my Bachelor's degree in Business Administration/Finance from University of Southern California and my MBA in Finance from California State University, Los Angeles. In August 1999, after being a stay-at-home mom with my twin boys, I came to Walden as an assistant in the Business Office. In my spare time, I like to read and travel with my family. My favorite travel destination is Bali, Indonesia.

Director Admissions

Billy Christian


Director of Annual Giving

Ludia Chae-Zerrudo

I have worked in Development for the past 8 years, and I am happy to join the Administrative team as the Advancement Officer and Database Manager. This is my second year at Walden. I am responsible for providing support and participating in all Development and Admissions activities, as well as providing vital organizational support by keeping all Walden students and their families’ information accurate, secure, and up to date, utilizing the database and online systems that the school employs. I hold a B.A. in Political Science from UC Irvine and a diploma in the Art of Cooking from the Art Institute of California, Orange County.

I enjoy spending quality time with my husband, son, and two dogs. I love to cook and travel. My most recent cooking project was making tequila lime seafood linguine.

Director of Communications and Events

Birthe Landerer

I am delighted to join Walden as the new Director of Communications and Events, and thrilled for the opportunity to contribute my experience in communications, fund development, and event management to advancing the mission of this special place.

I am originally from Germany, where I started out my professional life as a program manager in arts organizations, organizing multi-day international literature festivals, cultural events, and children's programs. I also taught German and Swedish in university and language school settings for various age groups. After spending my college years in Germany and Scandinavia, I graduated with an M.A. in German and Scandinavian literature, languages, and cultural studies (little did I know then that I would ever be living in the U.S.). I also hold certificates in public relations for nonprofit organizations, arts management, and German as a foreign language. Upon relocating to L.A., I started working in the field of development and communications for independent schools, most recently at an international school in the San Francisco Bay Area for the past three years. I thoroughly enjoy creating compelling communication and engagement strategies, and helping to build meaningful connections and relationships that support educational missions.

Walden's program resonates with me on so many levels; from its inquiry-based approach, globally minded outlook, amazing specialty classes and outdoor education trips to the encouragement of imaginative thinking and questioning the status quo. It is a joy to be part of a community of such thoughtful and creative faculty, staff, board members, students, and families. In my new role, I get to help bring Walden's mission to life by creating internal and external communication, fostering partnerships with families to create a vibrant environment, organizing mission-aligned events, and helping to increase philanthropic support for the school. I am grateful to be here and look forward to being a part of Walden's continued success in the exciting next chapter of its story.

Director of Curriculum

Kelli Dawn Holsopple

One of my favorite class assignments in graduate school was observing a tree. The sturdy silver maple was growing in the parking lot of Antioch University New England where I was getting a Masters in Elementary Education in their Integrated Learning Program. Every week I stood in the same spot in the parking lot, sketching my tree and writing observations. As I witnessed the steady, slow, and spectacular changes that took place through the seasons, I not only grew in knowledge about the scientific processes taking place, but I also started thinking in tree metaphors.

When I think about the Walden community, I think about a healthy maple: stable roots and ever growing leafy branches. Roots that stay deep and strong keep a tree standing and provide constant nourishment to the whole. From first getting to know Walden, I saw these roots: the powerful mission statement that guides the community. This mission and strong sense of purpose provide nourishment and strength to all of the incredibly dedicated teachers, administration, staff, board members, families, and students who bring this mission to life each day, in their own unique, beautiful way.

Branches full of leaves are also a vital part of a healthy tree system. They use source energy from the roots and synthesize it with captured sunlight to power the tree’s expansion in new directions, reaching higher and wider, providing more expansive and nurturing connections to its habitat. Walden’s dedication to this kind of growth and evolution, ever rooted in its mission, was also immediately clear to me through a strong commitment to professional development and intentional, reflective practices. These two forces, deep rootedness and visionary growing are what draw me to Walden and I am honored to join in these processes and begin growing with this vibrant community.

Here is a little more about me. I live with my wife Carolyn Ratteray, who is a professor of theatre at Pomona College in Claremont as well as an actor. Our family includes her brother and our nephew, as well as my sisters, parents, nieces and nephews who all live on the East Coast.

I have been an educator for 18 years and also have a background in theatre. Prior to attending graduate school, I was a full time social studies and imaginative inquiry consultant in NYC. I directed an imaginative inquiry (II) program in a K-5 progressive public school, designing and teaching integrated social studies units for all grades utilizing the pedagogy of imaginative inquiry. II is inquiry based learning that taps into children’s immense capacity for imagining, building, and playing. Together, the teacher and students create a story-line through which students are enrolled as experts engaged in accomplishing a mission or commission. They may become city planners, archaeologists, farmers, deep sea divers, or even step into the shoes of people from history, solving problems and making decisions. Highly collaborative, the curriculums engage students through exciting contexts for learning.

This summer I worked with colleagues from Little Red School House/Elizabeth Irwin, a progressive school in New York to lead the inaugural Institute for Imaginative Inquiry, bringing together 27 progressive educators from around the country to immerse them in the pedagogy of II. For the past two years I have also been working with the Middle Core teachers at Walden as a social studies/imaginative inquiry consultant and have been so inspired working with the teachers and students!

I am thrilled about becoming a full-time member of the Walden community. My first year will be spent listening and learning, attending to those roots I spoke of in order to find the best way I can support Walden’s ever growing leafy branches in their skyward travels.

Director of Finance and Operations

Meredith King

Learning Specialist

Janel Umfress

I have been the Learning Specialist at Walden School since 2006 and have worked in education for over 30 years. My primary role at Walden is to collaborate with faculty and families regarding students' learning. I work with faculty to establish classroom strategies and accommodations that enable students to access curriculum and effectively show their learned knowledge. I support families by providing continuity from year to year and by offering recommendations for outside referrals and resources.

Typically the process starts with a teacher or parent consulting me regarding a student's inconsistencies in learning. Often the discussion revolves around the student's difficulty in aligning work output with curiosity and intellect. It may also be that a child's behavior is reflecting signs of avoidance, disinterest in school, or challenges with peers - which can also be indicators of learning challenges. I believe that it is the job of educators and parents to peel back the layers to begin to understand the child's inconsistencies and to think about the skills that need building.

The teacher and I will discuss the student's strengths, current challenges and questions to explore and let the parents know that I will be observing in the classroom. I am not formally assessing the student, simply noting learning and behavioral tendencies and processes. I recognize that parents may be fearful of a label, yet this is not the focus or intention of the observations.

My goal is to note patterns and to always have the child's learning and success in mind. Meetings are held with parents, teachers, and me to discuss our multiple perspectives. We think about what may be impacting the student, how we can work together to be supportive of the child's learning, what skills need to be developed or strengthened, and strategies that can be implemented at home and school.

Front Office Administrator

Nellie Yoshimura