He was always that. He almost lost the Full House job because he didn't want to conform to that square dad character. He finally conformed because he realized this wasn't about him--there were dozens of other jobs at stake if the show fell apart.
I’ve noticed when it comes to wholesome roles there seems to be a pattern to cast the exact opposite in terms of the real life actor. Stephen Collins as the minister in Seventh Heaven comes to mind. The casting people know and I think it’s their big FU to the normals.
I didn’t know that. You are the font of info as usual. 😁