BURGESS MEREDITH: 

And what about good ol MICKEY GOLDMILL??  Mickey is the smart-mouthed owner of the gym Rocky frequently uses, and subsequently evicts him for good reason. The boxing trainer saw great potential being wasted on a measly job as a collector for a local loan shark. When he hears of Creed’s challenge, he offers to manage the club fighter but is initially rejected due to his harsh treatment. Rocky finally allows Micky to train him, and the two settle their differences.

ROCKY-then-Mickey Meredith was already an established actor by the time Rocky came along. After its release, he continued to find work in films like Clash of the Titans and The Last Chase. He never achieved leading man status like Stallone, but he did end up with a memorable part in Grumpy Old Men and Grumpier Old Men as a sex-crazed grandfather. Meredith died in 1997 at the ripe old age of 89. (screenrant.com)