When Roger León was still a high school principal, it was easy enough to gather his students in the auditorium and give them a pep talk.

Now that he’s superintendent of New Jersey’s largest school district, he needs a much bigger venue.

So during their first week back from summer break, all 12,500 eighth through 12th-graders in Newark Public Schools piled onto yellow school buses and rode to the Prudential Center in downtown Newark, where they filled the stands as León addressed each grade individually over the course of September 5-7. Alternating between administrator and emcee, and with the aid of the arena’s Jumbotron, he detailed graduation requirements, set sky-high expectations, and — for the ninth-graders — explained how they could join a trip to Orlando, Fla.

Behind all the specifics, the larger message he sought to convey was clear: Students are the raison d’être of his young administration.

“We’ve had many superintendents,” León said Thursday to the city’s ninth-graders, whose school-color shirts turned the stands into a palette of red, blues, and black. “We’ve had the state-operated-school-district superintendent, the community superintendent, the reform superintendent, the return-to-local-control superintendent.”

“I am none of those,” he told them. “I am the children’s superintendent.”

León, a 25-year veteran of the city school system who became schools chief on July 1, has had a busy few weeks.

Before school started on Tuesday, he summoned the district’s entire workforce to a staff meeting last week, also at the Prudential Center. At a separate meeting, he shared his ambitious goals for the year with the school board. Behind the scenes, he began making policy changes, including eliminating a program that extended the hours of struggling schools.

But the first week of school was mostly about the students.

On Tuesday, accompanied by the mayor and television crews, he visited the high school he graduated from (Science Park), the high school where he was principal (University), and the neighborhood school he attended as a child (Hawkins Street). At this last stop, he reverted to educator mode, offering encouragement to an eighth-grader who said he hoped to one day join the Navy (“We need great men and women in our armed forces — I’m proud of you”) and using a marshmallow to give seventh-graders an impromptu lesson on fractions.

During his Thursday meeting with ninth-graders, he shared his lofty goals for the year: perfect attendance at every school and all students passing the state PARCC tests. He announced that all ninth-graders this year will take the PSAT, a practice college-admissions exam usually taken by sophomores and juniors, eliciting some alarmed “What?!”’s from the crowd.

He also unveiled a new incentive program called “Newark’s Academic Challenge for Kids.” If the ninth-graders meet a long list of requirements each year — including maintaining a GPA of a least 2.5, pass the state tests, and participate in an extracurricular activity — then they will be eligible to go on a class trip to Florida in 2022.

“We’re trying not to leave anyone behind,” he told them, adding that they will still have to pay $800 to cover expenses.

After the meeting, as the students snapped selfies and headed back to their buses, León acknowledged that the convocation had been as much for his benefit as the students’. Having charged his employees the previous week with getting every student to pass the state exams — last year, only a quarter of students passed the math tests — he wanted to remind himself why it was necessary to set such a lofty goal, even if it borders on the impossible.

“That data wasn’t just numbers — it was these kids right here,” he said. “I needed to see them. I needed to bring faces to those numbers.”

If the talk galvanized León, it did the same to some students.

Jessica Jimenez, a ninth-grader at Bard High School Early College Newark, said she found the superintendent’s message “very inspirational and very motivating.” It also left her hoping León keeps up his end of the bargain.

“All the promises he made,” she said, “I really hope he fulfills them.”