Chris Rock returns to host Saturday Night Live this weekend, his fourth go-round as the show’s headliner. He's one of the show’s most successful alums, one of the greatest stand-up comics ever and part of the Adam Sandler repertory company of let’s-put-on-a-show pals. Yet, despite all that, Rock was never a great fit at SNL.

Some of that is on Rock, and some of that relative failure is on the show itself. For Rock’s part, he understood that he didn’t possess many of the skills that make Dana Carvey, Kristen Wiig or Eddie Murphy SNL naturals. Years after he was cast, according to oral history Live From New York, Rock asked Lorne Michaels why he got hired considering he didn’t do voices or characters, “anything particular that would help me on SNL.” Michaels replied that he believed Rock had “original thought.” Sandler says he...