Sarah Costello, a first-grade teacher at South Row Elementary School in Chelmsford, has been named a finalist for Massachusetts Teacher of the Year.
by Jen Oemig
CHELMSFORD – Sarah (Krasnovsky) Costello, a first-grade teacher at South Row Elementary School in Chelmsford, has been chosen as one of four finalists for 2026 Massachusetts Teacher of the Year.
A Connecticut native, Costello, 33, was notified that she was a semi-finalist back in April and was advised in early May that she had been chosen as a finalist.
Costello, who lives in Chelmsford with her husband, Kevin, said she has always dreamed of being a teacher.
“When I was 6 years old, I wanted to be a teacher more than anything in the world,” she said. “And one Christmas, I asked Santa for a chalkboard.”
Her wish for a chalkboard was fulfilled and Costello’s relatives bought her desks and chairs so she could set up a full classroom in the basement of her family’s home.
“I taught my stuffed animals, I taught my cousin’s girlfriends, I taught anything and everything in front of me,” she recalled.
After high school, Costello attended Salve Regina University, where she studied Early Childhood Education.
“There, I was the president for the Council for Exceptional Children,” she said. “We did events for Best Buddies and collaborated with different schools to do after-school programs.”
Following college, Costello moved back to Connecticut, where she served as a long-term substitute before securing a job teaching first grade at an elementary school in Watertown.
“My dream was to move to Boston to spread my wings and see where I could fly,” she said.
That dream landed Costello at South Row Elementary School seven years ago.
“I love the students who come through here,” she said. “I love the staff members; I feel like I couldn’t do this without them. We have great supports in place to help us service the kids’ needs. I feel supported by everyone. When you have those conditions, you’re able to become the best educator you can be.”
Costello said she feels incredibly fortunate to be in Chelmsford pursuing her lifelong passion.
“I love teaching first grade because I love the light bulb that turns on when kids are going through reading or math, which can be difficult,” she said. “After enough practice – usually around February and March – that light bulb turns on and you’re able to watch them grow into mathematicians and readers.”
In addition to her role as a classroom teacher, Costello is a Positive Behavioral Interventions and Supports (PBIS) and Multi-Tiered System of Supports (MTSS) facilitator at South Row.
Costello was nominated for Teacher of the Year two years ago by two different families and was asked to reapply last year. Now, she’s a finalist.
“I’m very passionate about what I do,” she said. “I really love to listen to people’s feedback and their ideas. I’ve worked really hard to make everyone feel included, and I feel that because of that and how I run my classroom, that somehow I’m here.”
As for her long-term aspirations, Costello said she’s on the right track to achieving one of her goals.
“Some people want to be administrators and move up that ladder,” she said. “For me, one of my career goals is to be Teacher of the Year someday. I know I work so hard and I put so much into it and it just means the world to me that other people see that too.”
The 2026 Massachusetts Teacher of the Year will be announced in the fall.
