What's a Nice Girl Like You Doing...? - S7-E7
Visible crew/equipment: After the last rescue it cuts to Roy as he says, "We'll catch you all a little later," and when Roy walks away we can see the actor's T-mark on the floor, where he was just standing.
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.