He established his acting chops once and for all.
TCM host this afternoon told interesting story about Ernie getting the role - he was working on the set of Bad Day at Black Rock with Spencer Tracy and told Tracy he wanted to take some time off to try out for a part in a little low-budget upcoming movie - at first Tracy wondered if it was worth the time, but after Borgnine told him a bit about the movie, Tracy encouraged him to go for it - the next year, Ernie won the Academy Award for Best Actor as Marty over, among others, Spencer Tracy in Bad Day at Bad Rock.....