The loss of Katz, 72, a lawyer, businessman, and philanthropist who was a co-owner of The Inquirer, remained painfully raw four days after he died in a plane crash in Massachusetts. In life, Katz made and gave away millions of dollars, but as speaker after speaker recalled Wednesday, he always said his most important job was father and grandfather.
Former President Bill Clinton spoke. So did former Gov. Ed Rendell, U.S. Sen. Cory A. Booker, Mayor Nutter, the historian Doris Kearns Goodwin, Inquirer editor William K. Marimow, and the comedian and actor Bill Cosby, a friend of 50 years.
Gov. Corbett, so often stoic, wiped away his tears with a handkerchief.
He described the happy incongruence of having the staunchly Democratic Katz stay at the home of a Republican governor. His wife, Sue, adored Katz, Corbett said.
Katz told her he had carved his initials under the bed he used in the governor's mansion when his close friend, Rendell, lived there. After the news of Katz's death, Corbett said, he saw his wife on the floor with a flashlight, hunting to see whether he had really done so.
Sue Corbett couldn't find the initials - but her husband assured the assembly they are there now.
Katz's memorial service filled the Performing Arts Center at Temple University, where he was on the board, and 200 other people watched a TV feed in an overflow room.
Throughout the 21/2-hour service, the mood shifted between mournful and magical.
There were laugh-out-loud stories, such as about the time Katz bet a friend in a receiving line that he could tell a dirty joke to a born-again Christian, President Jimmy Carter - and won the bet.
There was forceful exhortation, as when Cosby, resplendent in Temple T-shirt and sweatpants, told the crowd it must continue Katz's good works: "I'm not challenging you, I'm telling you - you better not let it drop!"
And there was wondrous encouragement, as when Clinton recalled how Katz, inspired by what he heard at a meeting, jumped up and pledged to build a charter school in his hometown of Camden, among the nation's poorest cities. "If more of us acted on our better impulses," Clinton said, "think what a different world we'd be living in today."
There were moments, too, of wrenching sadness, as when Katz's 14-year-old grandson, Ethan Silver, spoke evenly and eloquently of his love for his grandfather, and revealed himself as a child of remarkable poise.
"For as long as I live, Poppy Lewis will be in my heart," the boy told the crowd.
In a tribute video, assembled to appear almost as though he were speaking to the audience, Katz told people to seize the day, treasure their too-limited time, help their brothers and sisters in need, and, most of all, love their families.
"Life," Katz said, "is meant to have as much fun as you can conjure up."
The only sound in the hall was the rustle of women searching purses for tissues, and the strangled coughs of men trying to hide their tears. In the front rows, Katz's loved ones wept.
He and his late wife, Marjorie, raised two children, Drew and Melissa.
His longtime companion, Inquirer city editor Nancy Phillips, sat near the front.
Katz earned his enormous wealth through parking lots, billboards, and sports. He was a former owner of the New York Nets basketball team and the New Jersey Devils hockey team.
Four days before his death, Katz and H.F. "Gerry" Lenfest won a climactic auction for control of The Inquirer, the Philadelphia Daily News, and Philly.com over South Jersey power broker George E. Norcross III.
Katz was known across the region for his service on boards of universities and charities, and for his huge donations, which in 2013 included a $25 million pledge to Temple, his alma mater.
Katz started with nothing, losing his father when he was about a year old, while his mother worked to put food on the table. That childhood of need showed itself in the stories told Wednesday - of the $100 tips Katz left for waitresses, of the Super Bowl trip he bestowed on a coffee-shop worker.
Over time, Katz's influence and ideas touched almost every sphere of public life, from media to law, from politics to health care and education.
Booker, a rising Democratic star, told the crowd Katz was dismissive toward him at first, even after he won a U.S. Senate seat last year.
"Cory!" he said Katz told him. "Don't think you're anything special. Any idiot can get elected to office. And most idiots do."
The crowd roared, and Booker finished: What matters, Katz told him, is what you do once you're in office.
Booker said he believes Katz is in heaven. "I just hope he didn't go up to God and say, 'Hey, God, any idiot can create the Earth. But it takes special care to heal the world.' "
Drew Katz fought tears while he praised his father as a best friend, loving teacher, and careful adviser who was "tough as nails in business."
"My father prepared me for everything in life," he said, "except for this."
His sister, Melissa Silver, noted that people came to "honor a man who was a hero to the world," but "to me, he was just my daddy."
Katz was involved in his grandchildren's lives, attending every dance recital and tennis lesson, but worried he might die before they were old enough to remember him, she said. She pledged to him that no matter what, "you will never be a distant memory."
Katz collected celebrity friends the way some people collect stamps. But the friendships ran deep. One of the mourners, Shane Victorino, the former Phillies centerfielder, told reporters Katz was like a father to him.
"He taught me about giving back and what it means to help others," said Victorino, now with the Boston Red Sox. "I'll never get to see the man again and that hurts me."
Close friend Jerry Blavat, the DJ, was there. And the actor Steve Hytner, famous as the annoying Kenny Bania on Seinfeld. And former Pennsylvania State University president Graham B. Spanier, who lost his job in the aftermath of the Jerry Sandusky child-abuse scandal.
Spanier awaits trial on charges that he helped cover up Sandusky's crimes. But Katz, a close friend and Penn State donor, never backed away from him, the former president said.
"In my adversity over the last couple years, Lewis held me even closer," said Spanier, who maintains his innocence.
Some of those who mourned had never met Katz.
"I just read about him," said Carlos Johnson, a West Philadelphia resident. "It sounded like he set an example to be followed, and I just felt I should come and pay my respects."
At the end of a long entrance line stood Roberta West - who met Katz once, when he spoke to Temple students at the Legal Education and Participation Program, which she directs.
"I told him, 'You're only the third person I ever met who admits to being from Camden,' " she said.
Katz laughed, and they talked about being Camdenites.
"He radiated love and care and warmth and concern," West said, then shook her head over his loss. "Way too soon."