I am not referring to the Full House franchise which also made stars of Bob Saget, Candace Cameron, and the Olsen twins (twins sure were annoying on Full House though). But outside of Full House, John has had one and done Grandfathered, and Jake in Progress which also did terrible. Only reason ABC renewed Jake was out of spite so he couldn't join ER. Next season he joined ER anyway, but that show was a far cry from the dominant ratings it used to get and was nearing the end of its run.

But, he is considered sexy, so he gets a pass.

Also, John Stamos joined the cast of Necessary Roughness on USA in season 3 (ironically the only one I watched). Necessary Roughness was cancelled and did not get a season 4.

Hey! Maybe someone should create a series with Stamos, Ted McGinley, and who else? :)