The district started in March 1991. Twenty years later, it is a worldwide model for reviving weary downtowns and the go-to organization for managing problems that the city cannot.
Janet Calderwood, owner of a gallery that bears her name on Spruce Street, said the Center City District had helped keep her in Philadelphia.
"We're here because we love Philadelphia," she said, "but it was really awful in the late 1980s, early '90s. It was dirty. It was unsafe-feeling."
Once the district's street cleaners, in their eye-catching turquoise jackets, went to work, the difference was palpable.
"Other neighborhoods noticed," Calderwood said.
Of course, the Center City District is no urban cure-all. Crime is down but remains a problem, and Market Street bursts with discount stores blaring music so loud that the sidewalk seems to vibrate.
But in other parts of Center City, Philadelphians enjoy tapas at outdoor cafes and savor chocolate from gourmet shops. Little of that existed 20 years ago. Nor was there hope that Center City's population would grow as it did - up 18 percent last decade, to nearly 59,000.
Various trends, including the desire of younger people and empty-nesters to live in cities, converged to drive those numbers, but many business leaders say the Center City District deserves part of the credit.
"Paul had the chutzpah. He had the feeling that our city was going to take off," said Neil Stein, whose Striped Bass was a pioneer in the city's restaurant scene.
After 20 years, small is no longer CCD's mantra.
The district's portfolio has expanded to include cleaning subway concourses in Suburban Station, revamping the Parkway with green space and a cafe, lighting City Hall and Broad Street, and finding help for the homeless.
With an $18.7 million yearly budget, the CCD has completed $56 million in capital and streetscape improvements since 1991.
Levy seeks out ideas that get attention.
"We look for highly visible projects in the public environment," he said.
One example: the green, lollipop-shaped signs that mark the entrances to transit stops.
The district covers most of Center City's business and residential neighborhoods: 120 blocks and more than 4,500 properties.
It is roughly bounded by the Schuylkill on the west, Sixth Street on the east, Vine Street on the north, and Locust Street on the south, with extensions along the Broad Street corridor north to Spring Garden Street and south to Pine Street.
Its latest project - the $50 million overhaul of Dilworth Plaza, on City Hall's northwest quadrant, from a trash-strewn refuge for pot smokers into a park where people can picnic and listen to concerts - puts the Center City District literally on the mayor's turf.
For all its money and clout, the district has a few detractors. Former Pennsylvania Supreme Court Justice Russell M. Nigro and former mayoral candidate Tom Knox have sued the district, arguing that its assessments are unfair.
But Sheldon Bonovitz, chairman emeritus of Duane Morris, said most property owners, including his law firm, didn't mind paying.
"I just don't hear people complaining about the cost of the Center City District, and I think that's as good a litmus test as any that it's doing a good job," he said.
Levy is 64, leaving some to wonder whether his empire will survive when he's gone. But he said the district's board had discussed that issue. And, with a 14-year-old at home, he is not retiring soon.
A former house painter, Levy helped organize the district with Rubin, a developer, and Peter Wiley before the civic leader died in 1989. In some ways, Levy said, the job was easy.
"I often joke that I've never met anybody in 20 years in favor of dirty and dangerous," he said. "It's a motherhood and apple pie issue."
Contact staff writer Miriam Hill
at 215-854-5520 or email@example.com.