His wife, Yolanda "Lonnie" Ali, delivered a speech on his behalf.
"Muhammad has always believed that he lives within the great circle of humanity. He is, indeed, of the people," she said, quoting the Constitution.
"His care, his concerns, his well wishes, are all focused on the people within that great circle - we, the people," she said.
Nicknamed "The Greatest," Ali was considered the most famous athlete in the world at the height of his popularity.
Ali, who was diagnosed with Parkinson's in 1984, had to be held up on both sides as he walked shakily on and off the stage.
He sat with his shoulders slumped, his head tilted, and his gaze fixed, apparently to a large TV screen across the stage showing the speakers and prerecorded video.
A tribute video described the highlights of his remarkable life. He was born Cassius Clay in Louisville, Ky. He won a gold medal in the 1960 Olympics. He converted to Islam and changed his name after claiming the world heavyweight championship in 1964.
Not mentioned was his Philadelphia connection. During the early 1970s, Ali moved to Philadelphia, and he later lived in Cherry Hill.
Philadelphia also was the home of Joe Frazier, who became the world champion after Ali was stripped of the title three years earlier for refusing to fight in the Vietnam War.
His refusal, based on his religious faith, came in the early days of the antiwar movement and was cited as inspiration for the Rev. Dr. Martin Luther King Jr. to publicly oppose the conflict. On June 28, 1971, the U.S. Supreme Court voided his conviction for refusing to be drafted.
Nearly four months earlier, Ali had fought Frazier for the first time at Madison Square Garden in what was billed as the "Fight of the Century."
To the shock of his counterculture admirers, Ali lost to Frazier. But he won two subsequent battles, including the "Thrilla in Manila" in 1975.
"Muhammad Ali continues to this day to inspire young people throughout the world," said Mayor Nutter, who introduced four young boxers to the stage.
Other speakers included Joe Louis Barrow 2d, son of the boxing great Joe Louis; actor Terrence Howard, who played Ali in a TV movie; and retired NBA star Dikembe Mutombo, who spent two seasons with the 76ers.
"I was 8 years old when Ali came to my country," said Mutombo, referring to the "Rumble in the Jungle," Ali's 1974 victorious fight against George Foreman in Zaire, which is now the Democratic Republic of the Congo
"Forty years ago, Ali showed Africans that our lives mattered," Mutombo said.
Ali, who won the world heavyweight title three times, now lives in Scottsdale, Ariz., with his wife.
The Liberty Medal, first awarded in 1989, comes with a $100,000 prize.
Past recipients include Lech Walesa, Nelson Mandela, Colin Powell, Sandra Day O'Connor, Mikhail Gorbachev, Bono, and Steven Spielberg.
Contact Robert Moran at 215-854-5983 or firstname.lastname@example.org, or follow @RobertMoran215 on Twitter.