Translation:This is Teacher Wang's dad.
I was stuck on saying "This is Wang, the teacher's father." for a bit. I guess that's probably my brain on English. I feel like in English we would be more explicit about the teacher being named Wang somehow. Whereas I'm guessing in Chinese they might be more explicit if the opposite were the case, i.e. that Wang is in fact the father of the teacher. Or perhaps this sentence is just totally ambiguous.
个 (ge) is a measure word that should be followed by a noun: e.g. 这个人 (zhe ge ren) - this person, or 这个月 (zhe ge yue) - this month. You don't use 个 when 这 is followed by a verb, as in 这是 （zhe shi) - this is. So your first example is wrong, but your second one sounds perfectly good to me, but I don't know if Chinese speakers would ever say it this way.