It took one visit to Principal Ken Cuellar’s office this month for a kindergartner at Prieto Math and Science Academy to decide what he wanted to be. He was not there for discipline; he had asked for a tour.
He looked around at the desk, the chair, and the principal sitting in it, and decided the room would be his someday.
“Absolutely,” Cuellar told him. “I’m just holding it for you. I’m keeping it warm.”
For Cuellar, the son of immigrant parents from South America, that moment is the whole point. To him, representation and powering possibilities mean giving students the chance to see a future for themselves and believe it is available to them.
“It’s very powerful when I see people that look like me, that speak like me, and that have similar cultural backgrounds, holding positions that I never saw myself holding,” Cuellar said.
Cuellar has spent eight years at Prieto, four as assistant principal and four as principal, in the heart of Belmont Cragin. To him, a student picturing himself in that chair comes with an obligation.
“It’s an honor, it’s a privilege, but it also comes with a responsibility,” he said. “To ensure that they can walk into our building every day and truly feel seen, feel heard, feel valued, feel they belong.”
Principal Ken Cuellar of Prieto Math and Science Academy on Sept. 11.
Raising Leaders, Not Just Students
Prieto is a dual-language and Leader in Me school, and Cuellar traces that conviction straight into the curriculum.
“We truly teach students from pre-K on up that you’re a leader, and you don’t need a leadership title in order for you to be a leader,” Cuellar said. “You have the power to positively impact your concentric circles.”
For Cuellar, the lessons are not meant to stay in the building. He wants students carrying them home to their families and, eventually, into their communities.
“Now more than ever, our society lacks powerful leaders, transformational leaders, that can bring positive change not only to their families but to their communities,” Cuellar said. “That’s what we hope we’re able to do here.”
What Moved the Numbers
Prieto’s 2026 5Essentials results rose across the measures that describe how a staff works together. Teacher influence, quality professional development, and collaborative practices each climbed nine points from 2025 to 2026, while reflective dialogue rose eight points; all four are rated Strong.
The survey’s Effective Leaders section, which measures how teachers experience the principal, also rose eight points overall. Cuellar credits two things:
The first was time. When he stepped into the principalship after four years as assistant principal, the staff had known him for years but had not yet seen his vision for the school.
“People want to know ‘What is this guy about?,’ ‘What is the vision that they’re bringing?’” Cuellar said. “It’s our job as school leaders to be those drivers, to be those agents of change that can really galvanize the community, our students, our teachers, our staff, to truly believe in the work that is being done. That’s not something that happens overnight. It’s something that happens with time.”
The second was building other leaders. “Great leaders empower others,” Cuellar said. “It’s about being able to see something in others that they don’t necessarily see in themselves.” According to Cuellar, teachers and staff now lead many of the school’s initiatives directly.
This year, Cuellar joined The Fund’s Executive Principal Program as a Partner Principal to push these scores further.
Culture as a Strength, Not a Barrier
Hispanic Heritage Month runs through Oct. 15, and at Prieto the celebration is already underway. Nearly 94% of the school’s students are Hispanic or Latinx, though that figure hides how much Belmont Cragin has changed.
Over the last few years, what was once a largely Mexican and Puerto Rican community is now increasingly Ecuadorian and Venezuelan. Cuellar sees this as an asset.
“We truly view diversity as a strength,” he said. “When we talk about Hispanic Heritage Month, or we talk about representation, we really want that to not be limited to just one month, but be something that we show, and we do, every day.”
As applied at Prieto, that looks like a new figure from Latino history introduced through morning announcements and the social-emotional curriculum each day; it looks like a culturally relevant open house with traditional food and student artwork; and it looks like the parade of flags, a tradition of the last several years, where students carry the flag of their family’s country through the school in front of the full community.
“We see how the community comes in and feels welcome, and that’s what makes Prieto so special,” Cuellar said. He credits this tradition, in particular, with much of the school’s growth in family and community engagement, as families see themselves reflected in the building.
Fall Fest follows in October. In November, families bring ofrendas into the school for Día de los Muertos and tell stories about their ancestors.
For Cuellar, the through line is the message students carry out the door. He wants them to leave Prieto understanding that being bilingual, biliterate, and bicultural is an asset and a superpower.
The Year Ahead
Cuellar calls this one of the smoothest starts to a school year Prieto has had, which he attributes to the systems his team strengthened in advance and to a staff that wanted to be there.
Cuellar also attributes part of that to how he staffs the building; he looks for educators who are the right fit for Prieto, understand the community the school serves, and love their students.
Enrollment has been a harder problem. Belmont Cragin has lost nearly 1,800 students over the past decade, roughly the population of two or three schools.
Despite those pressures, he describes a united community.
“We see a new Belmont Cragin, a much more diverse Belmont Cragin, and that fills me up with so much joy,” Cuellar said. “Because I truly believe that there’s strength in diversity.”
The belief that representation changes what a student thinks is possible is why Cuellar did not laugh when a five-year-old claimed his office.
“That idea, that they can see that this is something that they can achieve, is everything.”
Ken Cuellar is the principal at Prieto Math and Science Academy, where he has served for eight years. Join us in celebrating Principal Appreciation Month and spotlighting how our school leaders power possibilities for young people every day.