Annette Hayes squeezed into a seat near the stage for the eighth-grade promotion at Mastery Charter School's Shoemaker campus in West Philadelphia because she just knew she was going to holler and cheer for her son, Leroy.

Hayes had plenty to shout about. Leroy, 14, won academic awards in math and social studies and took first honors for scoring 80 percent or higher on every benchmark test this academic year.

"I'm looking forward to next year already," Hayes said. "I feel grateful that I can send my son to a school where he can learn and is a really good experience."

Thursday's ceremony was more than a rite of passage for students and families marking the transition to ninth grade at the former Shoemaker Middle School. The event was a rousing finale to a year that saw the successful makeover of one of the Philadelphia School District's most troubled schools into a model charter school.

"I present to you the first freshman class of Mastery Charter School at Shoemaker," principal Robert Lewis announced, with a sweeping gesture toward the eighth graders. "Some people don't want to admit it," he said, "but these students here and the seventh graders in the back are one of the biggest success stories this city has had this year."

The school's testing showed students had gained one and a half to two years in reading and math. Discipline has improved dramatically at a school that had one of the highest assault rates in the district a year earlier. Students say their attitudes toward school have been transformed, and administrators say the change is visible in students' faces.

"When I first got here, they were so angry," recalled Jerel Brooks, dean of students. "They were really hard. Some kids just didn't smile at all."

He recalled the student who told him he had "survived" earlier grades.

"I said, 'You don't survive school. You learn from school,' " Brooks said.

Now, he said, he is surrounded by beaming faces.

"Just looking at them smile is great," Brooks said.

Mastery's approach aims to prepare students for college and beyond by enforcing a strict behavior code, offering a rigorous curriculum, and developing personal responsibility and interpersonal skills.

And while Mastery enforces rules firmly, it rewards good behavior and improved academics with pizza parties, no-uniform days and trips.

It all began in 2001 when Scott Gordon, a former businessman with an M.B.A. from Yale University, founded a charter high school to bring business acumen to education.

He recruited prominent business and academic leaders to the board of trustees, including Brook J. Lenfest, president of Brooks Capital Group, and Jeremy Nowack, founder of the Reinvestment Fund.

As a charter school, Mastery receives funding from the Philadelphia district: $7,248 per student and $15,346 per special-education student. Extra money comes from fund-raising.

A $2.65 million grant from the NewSchools Venture Fund in 2005 is helping Mastery expand. Based on Mastery's success with its Center City high school, the district asked it to convert Thomas Middle School in South Philadelphia to a charter school in the fall of 2005. In September, Mastery will open Pickett Middle School in Germantown as a charter school.

Shoemaker, which welcomed 208 seventh and eighth graders from the school's West Philadelphia neighborhood in the fall, is Mastery's biggest challenge yet.

In 2005-06, only 30.6 percent of Shoemaker's eighth graders scored proficient or above in math and 42.8 percent in reading on state tests.