It was a hot day in the 1950s at a beautiful park outside the city, and Carolyn Jenkins was a young girl excited to be on a trip with her friends from St. Charles Borromeo Church in South Philadelphia. The kids were ready to jump into a pool when someone told them: “Black people can’t swim here.”

Jenkins and the other children looked at the Rev. John van de Paer, the Roman Catholic priest who brought them on the trip. Without skipping a beat, the white man marched the kids to the Black pool and jumped right in himself, scandalizing authorities and demonstrating his love of and solidarity with the people of his parish, no matter the circumstances.

“That’s who he was — he was a champion for us,” Jenkins said.

Van de Paer turned 100 Sunday, and friends and former parishioners from South Philadelphia and Chester County feted the venerable priest with songs and video chats, with a drive-by at his current home in Arlington, Va., where he lives at Missionhurst, the American headquarters of the Congregation of the Immaculate Heart of Mary.

“Father John” is seldom at a loss for words, but when Jenkins and two dozen other St. Charles parishioners gathered on the church steps at 20th and Christian Streets, unfurling a banner with his picture on it, singing “Happy Birthday” and shouting out well-wishes on a FaceTime call, he hardly knew what to say.

“I love you all,” he said through the speaker. “I think of you every day.”

Born in Antwerp, Belgium, after the end of World War I, van de Paer grew interested in the idea of religious life and missionary work when he was in high school. He was ordained a priest and sent to the United States in 1947. In 1952, he was assigned to St. Charles, a Black Catholic church where he would spend more than 40 years.

It was a tough neighborhood, but van de Paer embraced everything about it, from the loyal churchgoers to the gang members who made sure he moved unharmed through the streets. He built the church into a social hub for the neighborhood, sometimes with his own two hands, as he did with the skating rink he constructed in the parish hall that’s now named for him.

Van de Paer always told seminarians that they shouldn’t expect to impose their will on the parish, that a priest’s job was letting the parish teach them.

He was an apt pupil himself.

Van de Paer stood in as father figure to many kids who lacked one, and often went to court hearings for young Black men in the neighborhood. He told teachers at the parish school they were never to expel Black boys for whom getting kicked out of school might mean entry into the criminal justice system or worse.

“He told us, ‘It’s your job as educators to work with them, to find out what they need,’ ” said Angie Baylock, a lifelong parishioner who taught at St. Charles School for a time. Baylock is now manager of the Newspapers in Education program at The Inquirer. “He was Black Lives Matter before Black Lives Matter.”

Neighborhood kids had opportunities because of van de Paer. He bought a Greyhound bus and took a group of children — some parish kids, others not — to Canada and the 1967 World’s Fair. During his time in the neighborhood, there were trips from Florida to Nova Scotia.

“He wanted to let us know there was a world beyond 20th and Christian,” said Baylock. “He exposed us Black kids to as much as he could.”

Later, when he reached retirement age and left St. Charles Borromeo, van de Paer spent nearly 20 years at Our Lady of Consolation in Parkesburg, Chester County, where he quickly endeared himself to a new parish as a man of the people.

When Kathleen Hood was planning a celebration for St. Malachi, one of the parish churches, she arranged for clergy to have seats of honor. She asked van de Paer, a man who prefers plaid flannel shirts to Roman collars, which exalted place he wanted.

“He totally disregarded the request,” Hood said. “He said he was going to stand on the ground with the people. He really is the people’s priest.”

That’s the title of a book Hood recently wrote about van de Paer’s life, a work scheduled to be published later this year. All proceeds will benefit the Equal Justice Initiative, the nonprofit that works to end mass incarceration and promotes racial equality.

Despite coming to Our Lady of Consolation in his late 70s, van de Paer transformed the parish with his energy — he often skipped days off. He personally restored St. Malachi in his late 80s, building doors, refinishing floors, painting and plastering.

And his homilies were inspiring, said Barbara Tuttle, a parishioner and friend. Listen to van de Paer preach and “you just wanted to walk out the door and go and be good,” said Tuttle. “And then he showed you how to be good by his example.”

Still sharp at the century mark — though he laughingly confessed Sunday to having some trouble with his teeth “because everything I have is 100 years old” — van de Paer said the celebrations in his honor were worth living for 100 years. He didn’t think he deserved the adulation, he said, but it was a lesson.

“I think it is very important that people feel that the church is for the entire community, so we can always help one another,” he said. “So that we can find out what the needs of the people are, and so that we are willing to give up some of the things we have and that they are missing. I’ve been teaching that in places where I worked, and I will never stop talking that way.”