In the first season actor Jack Riley (Mr. Carlen on the Bob Newhart show) made three apperances on the show. Episode 6, 16, 24. The problems is he played a different character on every show. That is not very consitant and all in the same season.

I have seen actors play one character on an episode of a series then come back and play a different character in another episode latter in the series but not in the same season.

I thought that was strange too, maybe he was friends with the producers or something.
When they started running DS over here last year I didn't think it was the same actor at first since he was in 3 close together.
He also appeared in a later episode 148- Blue Collar Drummond.

Another actor appeared in a lot of episodes, I can't remember his name but he played Arnold's mugger, barman, waiter etc.

Yeah I notice actors making frekent apperances playing different characters. But all those characters had small parts unlike Riley's characters. I don't why he wasn't cast on the Facts of Life. I though he did a good job on episode 24. Better than the guy they got to play the headmaster. It doesn't matter he would have fired anyone after one season because of the budget. Though nothing can top Mr. Carlen. That was a funny character.

Also the guy who played the director in the episode "Little and Mr. T" also played Mrs. Garett's son on The Facts of Life. Also the guy who played a bankteller in the episode when the bank is robbed also played a delevery man in the episode when Arnold pretents to wet the bed.

Originally posted by tvje
Also the guy who played a bankteller in the episode when the bank is robbed also played a delevery man in the episode when Arnold pretents to wet the bed.

He played the deliveruy man in quite a few epiosdes. I think he's Ben Starr's son.

Yeah, he probably was his son. I remember looking on IMDB and he'd only done I think 1 other small thing.
I wonder why Ben Starr left DS, I thought he was probably the best writer, and he was main producer.