The Rev. Michael V. Marrone, a former Catholic high school teacher, dreamed of opening a school for students who struggled in traditional classrooms and were behind in reading and math.

He envisioned using technology to hone in on the areas where students needed help, personalized instruction, and a curriculum tied to careers that would prepare grads for skilled jobs in the region's workforce.

After years of planning and some twists and turns, Marrone opened Liguori Academy on Tuesday as an unusual private school in Kensington.

"This is six years in the making," Marrone, the school's president, told supporters, board members, elected officials, staffers, and the 40 members of the Class of 2020. "We are very proud of the students we have here with us."

Educators know that ninth grade is a critical year for students, and that those who are behind in reading and math are most at risk of dropping out of school. Liguori aims to provide the extra help so those students can succeed and stay to graduate.

At this nontraditional school, no bells will mark the beginning or end of class periods, said Aaron M. Spence, the school's director of administrative services. Students will work in open, communal areas, and won't have assigned seats.

A priest who is on leave from the Archdiocese of Philadelphia, Marrone said the school is named for St. Alphonsus Liguori and is rooted in the concept of "boundless love" that the 18th-century Italian bishop, writer, and philosopher espoused.

Students came from an array of district, charter, Catholic, and private schools and said they were eager to be part of the first wave.

After graduating in June from Memphis Street Academy, a K-8 charter, John de Jesus, 15, said he selected Liguori for ninth grade over some magnet schools in the Philadelphia School District.

"I'd rather be in a school where we're forming our new school environment and culture," said de Jesus, who lives in the Northeast.

Former Memphis classmate Zoely Ramos, 15, of Kensington, said she was drawn to Liguori by the promise of one-on-one attention from teachers.

Frankie Spencer, 15, of South Philadelphia, transferred from John W. Hallahan Catholic Girls' High School in Center City for 10th grade. "I wanted to try something new, and I wasn't that fond of the all-girls thing," she said.

The school, which ultimately will be ninth through 12th grade, opened with ninth graders and a handful of 10th graders. It is modeled after an approach that was successfully pioneered at a school in California.

Liguori will use a special instructional data management system to regularly assess students' strengths and weaknesses. That information will be used to create a blend of individualized online instruction and teachers' lessons.

Pat Wright, the academy's director of educational planning, said that the computer-based approach had helped boost students' reading and math levels in a pilot program at several city schools and after-school programs during 2015-16.

Liguori's students will be grouped in four career clusters: energy; health and life sciences; information technology; and business and professional services. They will complete project-based assignments in those areas.

The school says graduates will leave with high school diplomas and industry certifications to equip them for jobs.

Annual tuition is $8,500, but Marrone said families will pay only 20 percent of that amount.

He said the school covers 80 percent, primarily through the state's Opportunity Scholarship Tax Credit Program. The OSTC program allows corporations to receive tax credits for contributing to scholarship organizations to help students attend nonpublic schools if the state has classified their neighborhood schools as low-performing.

At one time Marrone thought Liguori might become an independent school within the auspices of the archdiocese. But he and the academy's supporters altered course and applied to the School Reform Commission in 2014 to open as a charter school. The SRC twice turned down the proposal.

Liguori opened its doors as an independent school, at 1952 E. Allegheny Ave., in a building owned by Impact Services Corp., a community nonprofit, which is one of the academy's partners.

"It is my mission," Marrone said of Liguori. "Every system needs a place for students who need a nontraditional approach to education."

martha.woodall@phillynews.com 215-854-2789 @marwooda