Cassidy had been born in April 1950 into a show business family. He was the only child of Jack Cassidy, a Tony Award-winning actor as well as a singer, and Evelyn Ward, a TV and stage actress.
Ward died in 2012 of dementia, a condition that David would also be diagnosed with just two years later.
Earlier this year, David publicly announced his own battle with the illness. He was then forced to retire after the dementia began to seriously manifest itself, particularly in forgetting lyrics to songs he had been singing for decades.
Cassidy was then hospitalized last week suffering from liver and kidney failure. He was placed in a medically-induced coma, which he came out of this past Monday. Doctors were hoping to keep him alive until a liver came available for transplant, but he died the following day of liver failure.
It was a sad, struggling ending for a man who had exited middle age and was turning towards old age. But the fact is, few people are going to remember David Cassidy as a man in his 60's. They are not even going to remember Cassidy in his 40's or 50's.
As with most celebrities, David Cassidy is going to be perpetually in his 20's. It will be the Cassidy in youth, the one staring out at you from the picture that accompanies this story, that millions will carry in their mind for the rest of their lives.
Cassidy made his Broadway debut in 1969 in a show that quickly closed. But he was encouraged to make a screen test, moved to Los Angeles, and picked up guest appearances on a handful of big name television shows.
In 1970, Cassidy got his biggest break. He was cast in the starring role of 'Keith Partridge', the oldest son on a new television series "The Partridge Family" about a music-making clan headed up by a single mother.
The original plan was for the acting cast to do none of the actual music or singing for the show. But Cassidy lobbied for and won the right to sing, and his became the voice of the group on the show and in recordings.
The Partridge Family label created ten albums during its four-season run from 1970-74, and Cassidy sang lead on the vast majority of the songs. He also recorded a handful of solo albums during this period. The group received a 1971 Grammy Award nomination for Best New Artist, and also a pair of Golden Globe Awards.
Thanks to songs like "I Think I Love You", "I Can Feel Your Heartbeat", "I'll Meet You Halfway", "I Woke Up in Love This Morning", and "Doesn't Somebody Want to Be Wanted" the bubblegum pop sound of the band, and thus Cassidy's melodic voice, will live forever with fans of multiple generations.
This also leads to the larger point of this piece. Celebrities can often live forever. Think about it. Long after you and I, and likely anyone else reading this article, is gone from this orb the names, music, and works of numerous celebrities will keep them living on.
Artists who passed away in recent months, years, and even decades such as Elvis Presley, Frank Sinatra, John Lennon, George Harrison, Michael Jackson, Prince, and Tom Petty still have their music played regularly. Decades from now that is likely to still be the case.
The feats of notable athletes such as Babe Ruth, Muhammad Ali, Jim Thorpe, Jesse Owens, Arnold Palmer, Wilt Chamberlain, and Johnny Unitas are still remembered and celebrated. Again, decades from now that will still be the case.
On the Hollywood scene, acting professionals such as Marilyn Monroe, Alfred Hitchcock, Marlon Brando, Bette Davis, Orson Welles, Ingrid Bergman, Paul Newman, Philip Seymour Hoffman, River Phoenix, and James Gandolfini come to mind among many others. We'll be watching them perform for decades, as we already have been for some who have been gone that long.
That is to say nothing for notable political and historical figures such as George Washington, Julius Caesar, Princess Diana, Anne Frank, Albert Einstein, Leonardo da Vinci, William Shakespeare, Martin Luther King, Abraham Lincoln and more. These folks have lived on for not only decades, but in most cases for centuries after their natural lives came to an end.
Want to get even bigger? What about Jesus Christ? You can even set aside the nearly 2.5 billion people on the planet who, as I do, believe Him to be the living embodiment of God on Earth.
Any reasonable person would at least have to acknowledge that Jesus was a carpenter who became a preacher in the first century. Because of the strength of his message, he not only attracted followers in life, but he was put to death by those who feared his influence. That act led to a faith movement that is still going strong more than two thousand years later.
Now, don't get me wrong. David Cassidy is no Jesus Christ. His music and acting will not be around and followed in two thousand years - in all likelihood. But for as long as people who were exposed to and enjoyed his work live, and that will at least be decades to come, David Cassidy will live on.
Fame, fortune, adulation, influence. These are the drawing cards of celebrity for many people. Even those who claim to not seek those things are going to gain them if their work is powerful enough. Those things are going to frequently live on, long after the actual celebrity has passed on.
Unlike the rest of us, millions will remember celebrities for decades (at least) after their death. That will certainly be the case with David Cassidy. May he rest in peace, and may God bless his family and friends during this difficult time.