When Sister Rosemary Connelly took over as executive director of Misericordia, a group home for the developmentally disabled run by the Catholic Sisters of Mercy, there was a rule about children: The State of Illinois took them from the facility when they turned six. No exceptions.

But Connelly, who didn’t think much of state homes, ignored the edict. “The state license agents came and said, ‘Do you have children over six?’ ” she recalls. “And I said, ‘Yes, we do.’ And they said, ‘What are you going to do about it?’ I said, ‘What are you going to do about it?’ From then on, they left us alone.”

That was 45 years ago. Connelly, now 83, has been running Misericordia with a kind smile and an iron will ever since. Under her leadership, the nonprofit that began as a small nursing home on the Southwest Side now has nearly 1,000 staffers to serve the 600 children and adults who live on its 31-acre site in Rogers Park.

Connelly points out that until 1975 disabled people received only custodial care through the state, with no educational or therapeutic programs. Misericordia offers speech, occupational, and physical therapies, as well as yoga and dance classes. There’s an aquatic and fitness center, and residents work at a bakery and restaurant. “Our philosophy is based on the belief that our children and adults have a right to a good life, and they deserve to be engaged in that life,” explains Connelly, looking out over the campus. “Here they know they’re loved and challenged and respected.”

The years have mellowed neither Connelly’s drive nor her feistiness. Misericordia plans to open its 10th housing unit in 2015, and construction is progressing on four multiunit homes for its growing older population. Even Chicago’s pugilistic mayor knows not to mess with Connelly. One time, she notes, Rahm Emanuel “came up to me and said, ‘Sister, you scare me—’ ” She stops suddenly. “Oh, as a nun, I shouldn’t say the word he said.” (It rhymes with “witless.”)

Related: Chicagoans of the Year, 1994–2014