Why did Regis Philbin walk off the joey bishop show?

Regis Philbin did not walk off the Joey Bishop Show. He was a regular on the show from its inception in 1967 until its cancellation in 1969. Philbin was the announcer and, in the beginning, also acted as the "straight man" to Bishop.

It is possible you are confusing Regis Philbin with someone else. Do you have any other details about the incident you are referring to?