BOSTON -- For the first time in nearly two decades, students have enrolled at Catholic Schools in the city of Boston on all levels -- pre-school, elementary and high school -- in greater numbers than the previous year.

Elementary and secondary school enrollments increased to 7,706 students in the 2011-2012 academic year. This comes despite an overall decline in the school-age population of Boston, and increased enrollment at the city's charter schools.

According to Chris Flieger, area superintendent for the Office of Catholic Schools, the trend shows a move away from the declines in Catholic school enrollment persistent in Boston since the 1990s.

"It shows that parents are choosing these (Catholic) schools, I think is a big thing," he said.

Flieger explained the significance of increased enrollment in context of the educational plan within the Archdiocese of Boston.

"The enrollment is really starting to stabilize. It really ties in to what the schools are doing. The individual schools are strengthening their core academics. They are looking to expand out who they're recruiting to. I think that when they see these increases that only encourages them to do more," he continued.

In an email explaining the broad implications of the trend, Flieger pointed out that schools experiencing growth implemented changes toward increased recruiting and marketing efforts and continued traditions of excellence reflected in SAT scores. Some schools moved toward an academy model, but all focused on distinctly local involvement in the communities around the schools.

"The exciting thing that's going on is that its different things that the schools are trying, and most of them are successful," Flieger said.

Two of the 21 Catholic schools in the city of Boston, Cristo Rey high school and St. Brendan elementary school, both in Dorchester, experienced enrollment jumps of greater than 10 percent over last year. Officials at each school said the successful campaign to increase enrollment came on the heels of initiatives to assert each school's identity as an integral part of the local community.

Jeff Thielman, president of Cristo Rey Boston, said the school is currently working toward growing the student-body to 400. He said this requires admitting a class of about 125 freshmen every year, for the next four years.

He also said that increased enrollment at Cristo Rey brings greater financial stability to the school, allowing them to increase the reach of their mission.

"It basically means that we're able to grow our school, and we're able to provide high-quality Catholic, college preparatory education to more young people," Thielman said.

Students at Cristo Rey pay for much of the cost of their own education through the school's Corporate Work Study Program. In this program, students work a job outside of the classroom at one of 110 Greater Boston businesses, to pay part of their tuition. As a result, increased enrollment benefits the school budget with $1.9 million added this academic year, according to the school president.

"What's unique about our school here in Boston is that all of our students work to earn tuition, they work at banks, law firms, insurance companies -- some work at the Archdiocese of Boston," he said.

"We're going to cover about 58 percent of our costs with the work study program, about 12 percent with revenue from tuition that students pay," he added.

The remaining 30 percent of the schools budget comes through fundraising and contributions from foundations and individuals, Thielman said.

Through increased efforts on a local level, the freshman student body at Cristo Rey grew from 93 enrolled last year to 130 enrolled this year, a greater than one-third increase, according to numbers provided by the school.

"What this means is we have to go out and get more jobs, but we have been able to do that in this economy," Thielman said.

Moving forward, the faculty and staff plan continued engagement with the Dorchester community from the current location in the Savin Hill neighborhood where they moved after leaving Cambridge in 2010. Seventy percent of the students were residents of the city of Boston when the school was in Cambridge, according to Thielman. That number jumped to 89 percent after the move, he said.

"We are focused on serving kids from the city who would not have access to a college preparatory school otherwise," he said. "We moved to our base. We moved to get closer to the families we were serving."

Thielman said Cristo Rey will continue moving forward with the active, community-based recruitment model in the future.

"Over time, as our school grows to 400 students in the Cristo Rey model, it means that we're more economically self-sufficient. We reach an economy-of-scale that makes us sustainable," he said.

Maura Burke, the principal at St. Brendan School, said her school has increased enrollment by embracing a role as a distinctly Catholic element within the Dorchester community.

"We are a neighborhood, parish school," she said. "We remain independent and reflect our community's identity."

Burke said enrollment has increased 21 percent, helping the school serve the community.

"The increase in students has increased our ability to help those around us," she said.

St. Brendan students recently filled 95 Thanksgiving baskets for donations to the St. Vincent DePaul Food Pantry and raised $2,000 in two weeks for the Leukemia and Lymphoma Society through the school's Pennies for Patients Service Project.

"We have a culture in our school that has become more electrified," she said.