Having three different principals over nine months would be disruptive at any school, but a Brooklyn high school got through the chaos with a huge assist from its chapter leader.

Last May, the longtime principal at FDNY Captain Vernon A. Richard HS for Fire and Life Safety was removed unexpectedly.

“It happened so quickly,” Chapter Leader Stephanie Isidore said. “We saw him on Friday, then we get an email Sunday informing us, and then Monday, he’s not here. It was shocking.”

Earth science and biology teacher Samuel Fawundu said Isidore was an immediate source of comfort and information.

“Ms. Isidore immediately called a staff meeting to explain what was happening and gave members the opportunity to discuss our questions and concerns,” he said. “This gave us a great sense of relief, and in fact, may have even helped bring us closer by keeping our focus on the students and reminding us why we are here.”

Within a few days, an interim principal was appointed. But a marked change in leadership style created tensions that resulted in Isidore having to file a number of grievances on members’ behalf.

“I needed to have many conferences with the principal and members to try to deescalate and reduce the amount of grievances,” said Isidore, who has taught science at the school for 10 years. “This school year, I filed more grievances than I’ve ever filed or have known the school to file.”

With January came a new year and yet another change in principals — and a new leadership style to navigate.

However, the new principal’s style has been a better fit within the school’s culture, said Isidore. “She’s very visible — like our first principal,” said Isidore. Other than a brief hiccup over student cellphone distribution that was quickly resolved, Isidore said things are getting back on track.

Through it all, Isidore has been a rock for her members.

Managing the changes in leadership was challenging, said English teacher Amanda Gillespie, but Isidore provided a steadying influence.

“She’s an incredible leader,” Gillespie said. “She always kept us informed via email, meetings and by doing personal check-ins,” and also continued to “advocate for our rights” to help “with these major transitions.”