In 1980 the school became fully co-educational by allowing girls to continue past the second grade, thus graduating the first co-ed senior class in 1992.

The school's Center for Public Purpose engages students in service and community-based work by addressing Philadelphia's most pressing social issues, particularly education, food insecurity, and poverty.

To earn an activity credit, many Upper School students complete 40 hours of community service a year; a van carrying students leaves the campus after school every day to perform community service in various locations throughout the Philadelphia area.

The honorific "OPC 1689" is bestowed rarely by the Overseers upon significant faculty and staff in recognition of their service to Old Penn Charter.

During the last week of classes before the winter recess, the group greets the community with holiday music on the Senior Stairs in the morning.

Later that year, on October 22, 2022, the Board of Trustees announced the selection of Karen Warren Coleman as the next Head of School, who started in the fall of 2023.

The show's creator, Adam F. Goldberg, is an alumnus of William Penn Charter School, an OPC 1994.

Schooled, a spin-off of The Goldbergs also features the fictional William Penn Academy as the primary setting for the show.

Penn Charter has notable alumni in the arts, sciences, government, and business, including Grace Kelly, Rubén Amaro Jr., David Sirota, Matt Ryan, Robert Picardo, Adam F. Goldberg, Mark Gubicza, Michael Siani, Leicester Bodine Holland, Richard B. Fisher, Arthur Ingersoll Meigs, Richard Lester and Vic Seixas