This article is part of a twin profile. Read the companion piece on Ashlynne Thomson’s departure here.
After an impactful 19-year career of teaching, advising, coaching, and sitting in classrooms across Moorestown Friends School, Clark Thomson plans to retire at the end of the 2025-2026 school year.
Thomson had 16 years of experience teaching at the Darrow School before working at MFS, where he had served as the Assistant Head of Upper School, or the equivalent of Upper School Head. He said the move to MFS came after realizing he had taken on a role at his previous school — Assistant Head — that had taken him out of the classroom he loved so dearly.
By the time he leaves, Thomson will have completed a total of 35 years in education.
He began his career at MFS in 2007 as History Department Chair, a role he held for 16 years before choosing to downsize his administrative responsibilities and become a history teacher solely, teaching The Rise of Nationalism, Hayek vs Keynes: The Economic Argument of the 20th Century, Cruel and Unusual: An Examination of the 8th Amendment the Death Penalty, and Comparative Government. Throughout his time at MFS, Thomson has also taught economics, coached Middle School tennis, and served as an Upper School and Model United Nations (MUN) advisor.
Thomson recalled arriving at MFS with clear instructions from the Head of School Van Meter: help rebuild a department where several faculty members were leaving, support the new teachers coming in, and guide the department through a transition period. That role — part teacher, part culture builder — would define much of his time at MFS.
At the same time, he and his wife, Associate Director of College Counseling Ashylnne Thomson, who also taught at Darrow School, were looking to step away from the “all-encompassing nature” of boarding school life. There, he explained, he was effectively “on” all the time: he lived where he worked and was constantly surrounded by his administrative duties.
The move to MFS allowed him to return to a role centered on students and teaching rather than primarily administration. But colleagues say he never really stopped living like someone whose life revolved around a school community.
Upper School English teacher Debra Galler, who worked alongside Thomson as a fellow teacher, said Thomson’s presence was felt well beyond the walls of his classroom.
“[Thomson] is like a big brother,” Galler said. “He makes fun of me a lot and interrupts my classes, and genuinely is a menace, but also is extremely supportive and caring.”
Students of Galler are familiar with Thomson’s interruptions. He is known to sit in on their classes and participate in them, whether invited or not. Though she talked about his disruptions with mock disdain, she expressed that Thomson was actually an integral part of her classes and the culture within them.
“He’s been in so many different class days, but it’s actually been amazing. He joins in the discussion, right? He shows the students that these topics extend beyond just like we’re doing this because we’re in this classroom, like, they actually have relevance,” Galler said.
To Galler, Thomson’s “chao[ticness]” represents the important parts of MFS’s learning culture. Though he can be disruptive, he truly cares about building a strong community and ensuring that students love what they learn.
“[It’s] the sense [that] we are a learning community, and it’s not just people in their individual rooms doing their individual thing: that’s very Clark.”
Thomson described the energy Galler referenced as something that has stayed the same for decades.
“I am passionate about my subjects, probably to a fault. As anyone who’s had my classes knows, I can get off the subject and start ranting about something else,” he joked.
That intensity, he said, is part of how he teaches, enabling him to connect with students.
Much of Thomson’s work at MFS centered around connecting with students and helping them take ownership of the spaces they existed in. He described inheriting programs where students sometimes participated for appearances rather than genuine engagement.
“I did a lot of work with leadership on changing that [superficial] culture,” he said. “That culture took about a decade to change.”
Former Thomson student and MFS alumnus Vanya Weinstock ’23 corroborated Thomson’s work, describing how Thomson’s honesty shaped his growth as a leader.
“He wasn’t afraid to point out things I was doing wrong,” Weinstock said. “Because of that, I was able to learn a lot.”
Weinstock added that Thomson’s critiques showed real care and that his compliments felt meaningful because they were direct.
“He truly cared about my growth … even if that [meant] sacrific[ing] my feelings in the moment,” he said. “He truly has a care for his students that’s unlike any teacher I’ve ever had … He was one of the best things that happened to me in high school.”
Weinstock also noted that Thomson continued writing to him after graduation, a tradition he’s begun doing with students he has gained a special connection with outside of school.
“When I went to college, he continued to send me letters and ask how I was doing,” he said.
Another student of Thomson’s, Grace Graefen ’26, also commented on the connection she and Thomson have. “I would just say that he was the first teacher I bonded with in Upper School and was a safe place for me throughout my time here,” she said. “He also influenced me to love learning.”
Thomson said those kinds of ongoing connections are what mattered most to him over the years. When asked what he would miss most from MFS, Thomson easily cited his students.
“I think I have had a lot of impact on a number of students every single year,” he said, describing the “uncle-like, mentor-like” relationships he built over the years. “That reinforces my love of this job.”
Thomson said the decision to leave is part of a broader downsizing plan rather than a traditional retirement. He and Mrs. Thomson plan to move to Vermont, where they own a home, and hope to find part-time or volunteer work that allows for more balance.
“We want to enjoy things in a bit of a different way,” he said. “We may find out we’re giving up more than we realized.”
He mentioned continuing to pursue his love of teaching, whether that be teaching classes at a local library or stepping into schools when they need someone for an extended leave.
He described meeting a teacher years ago who came in to fill a sudden vacancy and told him, “I see myself as a fireman. I come in, I put out fires, and I leave.”
“That really stuck with me,” Thomson said. “Not [being simply] a sub, but [rather] a long-term substitute teacher … impactful enough that students can get to know you.”
