Macchio is older than Thomas Ian Griffith.
Macchio was dreadfully unhappy about having to do III. He felt constrained by the role, that it had cost him any serious consideration for the lead in About Last Night. But he was contractually obligated for a third installment.
When the film began production he was twenty-seven years old, and had just gotten married. The girl in the film was eleven years younger than him (she was sixteen), which made things so awkward on screen that they re-wrote the script to have her go away halfway through the movie.
And he didn't even get to do any fighting in the final round, just some strange sideways dancing.