Mourinho, who was touted as a possible replacement for Ferguson, maintains former Everton boss Moyes deserves his shot at one of the highest-profile jobs in world football.
"They have made good decisions," he said.
"David proved himself at Everton. Okay, no trophies, but it's not easy to get a trophy when you manage Everton and he was not far from doing that.
"He has good experience, good work. I am more than happy, and I feel very happy for him.
"Man United will give him the time to adapt to a new dimension.
"He has never played a Champions League match so people can't expect him to be a fish in water in that first match.
"Give him time, stability. United is perfect for that, so that's a very good choice."