MacMullen will take over on July 1 for Dr. Eric Ruoss, who leaves the school after two years.
MacMullen has spent 30 years working at Hopkins School in New Haven. While at Hopkins School, MacMullen rose from a chemistry teacher to chair of the Science Department and then dean of faculty.
She earned a chemistry degree from Denison University, where she also studied Spanish, ballet and Afro-Caribbean dance.
In May, MacMullen will receive a master's of Education in Independent School Leadership from The Klingenstein Center at Teachers College at Columbia University.
“I greatly look forward to getting to know the current generation of students and their families and closely working with the faculty and administration,” MacMullen said. “I also look forward to connecting with the alumni of this esteemed school and understanding what Kew-Forest has meant to legions of students over the years.”
Kew-Forest has 250 students from pre-kindergarten to 12th grade. Next year the school will celebrate its 100th anniversary.
Board chair Gregory L. Matalon said the board felt comfortable with choosing MacMullen.
“We consistently saw a strong and thoughtful leader, a superior level of preparation and analysis, and someone committed to our values of diversity and inclusion,” he said.