Keirans, 23, of the city's Somerton section, said the corps aimed to blend socializing with public service and provide an outlet so Catholic high school graduates "can make an impact in Philadelphia."
After earning a business-management degree in 2010, Keirans landed a management-consulting position that requires frequent travel. While on the road a year ago, he thought about how much he missed the sense of being part of the community from his high school and college days.
He came up with the idea of forming a group for young adults who had returned to Philadelphia after college and shared a background in Catholic education that stressed academics, athletics, faith, and service.
Friends from Penn State were enthusiastic.
"After Penn State was over and we were all back in Philadelphia, this seemed like a natural fit," said Tom Shakely, an alumnus of Archbishop Wood High School in Warminster and vice president of the group's board.
On the main Penn State campus, Shakely said, there is such emphasis on community spirit. But afterward, it is absent in day-to-day life.
The corps shows young professionals "there is still a way I can give back to my community," said Shakely, 25, a media consultant for nonprofit groups and parishes. "That was compelling, and I think there is a lot of passion for this."
To determine whether a group like the corps was needed, Keirans and others met informally with several priests and other religious leaders, but the group is not affiliated with the Archdiocese of Philadelphia, Keirans said.
News of the nonprofit group quickly spread by word of mouth and social media. Though most of the recruits so far are ages 23 to 26, they represent an array of private Catholic academies and archdiocesan high schools.
"I thought it sounded like a great idea," said Christen Kouch, 22, a member of the Class of 2007 at Mount St. Joseph Academy in Flourtown, who met Keirans in high school. "He had a lot of great ideas from the very beginning. . . . I just wanted to be a part of it."
At "The Mount," Kouch was busy with sports, student government, and community service. But as a nursing student at the University of Delaware, she had little extra time.
Kouch, who graduated from Delaware in May, is a registered nurse at Children's Hospital of Philadelphia. Now she is on the corps board and helping with projects.
"It was great to be able to get back to that and do something to give back," she said.
According to its vision statement, the group plans to undertake three or four large-scale projects a year to help neighborhoods and forge new relationships "through shared experience and mutual interest in volunteerism."
Leaders have met with city officials and contacted city organizations to discuss other projects, but painting the former convent at St. Thomas Aquinas was the group's first effort.
Through his media-consulting job, Shakely had been working with the South Philadelphia parish. Late last year, just as the corps was getting organized, Msgr. Hugh J. Shields, the pastor, mentioned his dreams for the former convent.
The building had been used as a day-care center, but that program had moved to the parish school. Shields wanted to spruce up the building and make it a center for the Vietnamese, Mexican, Indonesian, and other families in the neighborhood. But the parish needed help.
Corps members met Shields and looked over the building. About 30 arrived one Saturday in early February to begin prep work. Two weeks later, 100 showed up for a day of scraping, painting, and overall beautification.
The parish provided paint and supplies; the corps supplied the labor.
"I thought there was a good energy and sense of giving back," Shields said. "They were very helpful, and I think it was good for them, too."
He said the parish appreciated the work that gave the parish center a jump start. Corps members also have promised to develop a business plan to help cover the center's utility costs.
When Shields thanked corps members, he said they all told him they were happy to be able to help.
"It was not just a pro forma kind of thing," Shields said. "There was an energy and a spirit you cannot pay for."
Information about the Philadelphia Catholic League Alumni Corps is available at http://phillycatholics.com/
Contact Martha Woodall at 215-854-2789 or firstname.lastname@example.org.