DORCHESTER (CBS) – Mayor Marty Walsh and new superintendent of schools, Dr. Brenda Cassellius, arrived at the Jeremiah Burke High School Thursday morning to find the smiling faces of students, teachers and other staff members on the first day of school in Boston.

”I’m feeling really excited,” said senior Isaiah Pina. “I’m ready to get right into class and start doing what I always love to do.”

One of the first two through the doors, Mayor Walsh and Dr. Casselllius were ready to bring what she calls “the juice.”

No, not a drink. Instead, it’s a mixture of core values – collaboration, inclusion, equity and joy. One, however, was missing until Dr. Cassellius got to Boston.

“I was at a principals’ meeting and one of the principals raised their hand and said ‘if you add unity to that then you have the juice’ and so we all had a big laugh and said ‘let’s bring the juice then!’ So now Boston Public Schools is bringing the juice and bringing the joy,” Dr. Cassellius said.

Boston Public Schools superintendent Brenda Cassellius greets parents Thursday morning.

Each student chose a value of their own in the form of a pin. “I am really happy about this. It’s unity,” Pina said.

Mayor Walsh remembered how he always felt on the first day of school. “I wasn’t a great student, so on the first day of school, I had this idea this is the year. I am going to do all the homework, going to do it all. It has always been exciting,” he said.

Junior Katio Barbosa was thrilled to see the mayor and superintendent walking the halls.

“It’s boosted my confidence for the year and makes me want to do even better,”she said.

Though this is Dr. Cassellius’s first day of school too, she already has ideas.

“Making sure our teachers are supported in the classroom. Making sure that kids are coming to school every single day and working with our families to ensure that they are here because you can’t learn if you’re not in that seat learning,” Dr. Cassellius said.

Before the tour, she went to the school bus yards to greet people. On Wednesday, she knocked on the doors of several Boston neighborhoods to meet students and their families.

“I met a second grader that I said… I hope I’m handing you a diploma in 10 years,” she said.

So what’s today’s takeaway for the rest of the school year?

“Lead by example and not lead by being the biggest or funniest kid or the biggest mouth in the classroom,” Mayor Walsh said. “They lead by example…by the way they carry themselves, the way they interact with other people…that’s a leader and I’ve told them to continue to do that.”

Several students told WBZ-TV they’ve already been taking this advice by reaching out to younger students to make sure they feel comfortable at school.

As for the new superintendent, she says everyone can expect to see her at many Boston public schools throughout the academic year.

Lisa Gresci