Answer
Philip Drummond was portrayed by Conrad Bain throughout the entire run of the popular sitcom "Diff'rent Strokes," which spanned eight seasons from 1978 to 1986. During this period, Bain's age ranged from 55 to 63 years old. This means that Bain was in his late fifties when he first took on the role and continued to play the character well into his early sixties.