He said it was a "fabulous experience" and would recommend it to anyone in a heartbeat.
Mr Brady said he believed everybody should do something which was a little bit scary in their life, and Mastermind had given him that challenge.
There had been a certain amount of stage fright beforehand, but nothing he could not handle, he said.
With a 37-year career as a radio announcer, he said he had learned how to deal with nerves and how to "get the butterflies flying in formation".
He had done extensive study and reading around his specialist subject, which he said was the only one of the three categories that could be prepared for.
There were three 90 second categories of questions which consisted of the contestant's specialist subject, general knowledge and New Zealand general knowledge.