New headmaster named for Riverdale Country School


Riverdale Country School will end the school year with a new head of school as longtime administrator Dominic Randolph announced this year will be his last.

After 15 years, he is stepping down and handing the position to New Jersey native Karena Ostrem.

With 25 years of experience, Ostrem will be the seventh head of school named in the institution. She spent her time as an educator in independent, public, and charter schools.

The job is somewhat familiar to Ostrem as she served as the founding head of school at the Haile-Manas Academy — the first nationwide residential school in Ethiopia.

The academy is a private co-educational college preparatory boarding school that provides world-class education. As she built the academy from the ground up, she instilled her values to the students to achieve their highest potential.

“I’m honored to join Riverdale Country School and am inspired by the legacy that Dominic has built with this dynamic community,” Ostrem said. “When I look at Riverdale, I see a forward-looking place where all students have an opportunity to thrive — inside and outside the classroom.”

Ostrem has educated high school students in the most successful public, charter and independent schools in the Northeast. She was an adjunct professor in mathematics education at City College and a full-time math and science teacher at Vanguard High School. Prior to that, she was a co-founder of the public Bronx Lab School in New York City where she implemented an innovative curricular vision including integrated math and science and senior capstone projects.

As the academic dean at The Lawrenceville School, an elite college preparatory boarding school in Lawrenceville, New Jersey, Ostrem led and fostered a diverse community of faculty and students. She designed the service-learning program and led teams that advanced student opportunities for independent work.

She was also a founding faculty member of the Island School, an innovative semester program in Eleuthera, Bahamas, focused on sustainability and science research.

She earned a BSE in civil engineering from Princeton University in 1997 and a MS in environmental engineering from Columbia University in 2004 and a professional certificate in school leadership at Baruch College.

River Country School, Dominic Randolph, Karena Ostrem, Haile-Manas Academy