In the halls of high-achieving Northview High, students are given the freedom to play guitar, hang out with friends and talk on their cellphones during lunch period.

They’re also pressured to compete with each other academically, creating an environment that educators say drives up grades, test results and graduation rates.

The Fulton County school, in the affluent city of Johns Creek, was the top-performing traditional public high school among 15 school districts in metro Atlanta in 2013, according to the Georgia Department of Education’s evaluation released Monday.

How does Northview High do it? Principal Paul Brannon said students are expected to meet difficult academic challenges, and then the school provides tutoring and extra access to teachers so students can prosper if they make the effort.

“It’s a very competitive environment. Our kids want to be the best. They want to be successful,” said Brannon, who has led the 1,900-student school for three years. “Sometimes we try to figure out ways to lessen the pressure, but they push themselves.”

With a student body that’s 46 percent Asian, 43 percent white and 11 percent black, students learn from their various backgrounds to create a school culture that’s focused on achievement, Brannon said.

“Students here are so used to competition and outdoing each other,” said Marri Kang, a junior in a news magazine class.

The median household income in Johns Creek was $109,553 from 2008 to 2012, more than double the $49,604 median household income statewide, according to the Census.

Nearly every graduating senior last year enrolled in college or joined the military. The school’s four-year graduation rate was 94 percent.

In the cafeteria during lunch, it isn’t uncommon to see students studying and snacking at the same time. About a dozen parents handed out root beer floats to seniors Monday, part of a monthly effort to provide them treats. The parents estimated that more than 500 people volunteer at the school in some way.

“There’s a culture of expectations and support,” said Ellen Li, vice president of finances for the parent, teacher and student association, as she prepared the floats. “The kids are very motivated and self-driven. If they can succeed in Northview, they can succeed elsewhere.”

When students need help with their homework or preparing for exams, teachers make themselves available to answer questions by email or through the school’s website.

They can get one-on-one assistance at school or attend tutoring groups, said Ashley Ulrich, who teaches English to freshmen and sophomores.

“We make sure students have access to what they need at whatever level they’re at,” she said.

Northview High offers 29 out of 31 possible advanced placement courses. The only AP classes missing from the school are Japanese and Italian languages, Brannon said. About 75 percent of seniors take at least one AP class.

No student had a grade point average last year below a 70, which is roughly equivalent to a low C, Brannon said.

“You can learn just as much from other students as you can from teachers. They’re all smart here,” said sophomore Ashianna Jetha during lunchtime. “The students motivate each other.”

The school earned a score of 93.9 on the state’s College and Career-Ready Performance Index, which distributed grades on a scale from zero to 110.

Northview High scored well on the portions of the index that account for standardized test results and academic progress, and the school also earned the maximum score for closing achievement gaps because its lowest-performing students exceeded state averages.

“We have a variety of races here, and that’s what makes us different. It diversifies the community,” said senior Seong Su Kim, the president of the Student Government Association. “Everyone strives to do their best, and everyone is pushing each other.”