Best vs. Best Supporting--totally random

Best vs. Best supporting is really arbitrary. It's up to the Academy on whom to choose and there are no set rules. And as we know the winners are usually not the best performances/films.

So William Holden won for Stalag 17 even though he was on screen for 25 minutes. And Robert Strauss in the same film was nominated for Best Supporting even though he was on for an hour.

David Niven for Separate Tables was on for 24 minutes.
As for the Godfather, Marlon won Best Actor, but was on screen for 40 minutes; Al Pacino was best supporting, though onscreen for 1 hour, 6 minutes, 22 seconds.

And Network: Peter Finch won Best for a 33 minutes one. And Beatrice Straight won Best supporting for ....wait for it...a 5 minute performance!

https://www.goldderby.com/feature/best-actor-oscar-winners-shortest-performance-record-1203945798/

https://www.goldderby.com/feature/best-supporting-actress-oscar-winners-shortest-performance-record-1203929391/