He lived a long fruitful life so I'll list some of my favorite films he starred in.
The Caine Mutiny
The Last Time I Saw Paris
Men of the Fighting Lady
Battleground
Go For Broke
Command Decision
Thirty Seconds Over Tokyo
A Guy Named Joe
The Human Comedy
State of the Union
Scene of the Crime
The Bottom of the Bottle
23 Paces to Baker Street
Brigadoon
Yours, Mine and Ours
His war films such as Battleground, Go For Broke, Command Decision and Thirty Seconds Over Tokyo are among my favorite films of that genre. I watched those fours films at least once a year.
Also, The Human Comedy is another yearly viewing ritual that goes back to my childhood usually around this time of the year. The film noir Scene of the Crime is very good and I've been trying to catch another viewing of 23 Paces to Baker Street.
Of course, The Caine Mutiny speaks for itself. Overall, he had a lot of films that I considered among my favorites. He was almost killed in a car accident 65 years ago that left him with a head scar you can noticed when watching his films, that accident almost decapitated him.
I loved all of his films. But, my favorite Van Johnson film is, "IN THE GOOD OLD SUMMERTIME", with none other than the great Judy Garland. He will be missed. The great thing of course, we have all of his films to savor in the future.