The first time Louis C.K. hosted “Saturday Night Live” in 2012 it was quite an event — one of those high water marks for the show.

His return Saturday seemed planned around the hope hat his mere presence would carry the show.

And while his monologue went unusually long — and even could have gone longer — eventually he was going to have to be in skits, which, in the recent tradition of the show, ran out of gas a little more than halfway through.

He wasn’t part of the cold open, which involved President Obama going out for viral messages after the success of his “Between Two Fermns” appearance with Zack Galifianakis. To further his success, a consultant has him wear Pharrell’s hat, pose for selfies with Kim Kardashian and Harry Styles, do a Vine with the Pope, and kiss Justin Bieber.

C.K.’s monologue was a rangey, free-wheeling thing, full of asides and near-edgy observation about hunger, the existence of god and use of an offensive term, “wife beater,” for a piece of clothing. He could have gone on for half an hour and the show would have been successful.

He stepped in as a Black Studies professor for the skit Black Jeopardy, which was funny but didn’t have much of a punchline.

Meeting a boss who has the body of a baby was a revival of a character previously introduced by Beck Bennett — basically the imitation of a grown man who thrashes like a baby and spits up. The recurring punchline: when the co-worker played by C.K. talks baby talk to him and he recoils: “But I’m a grown man!” Still, it was the last good part for C.K. for the whole rest of the show.

In his other appearances, he was the butt of a group of women on a Brooklyn stoop who sing “Mr. Big Stuff” to him as he replies “Are you referring to me?” and “I am Mr. Medium Stuff at best.” No punchline there. It’s followed by a doctor’s skit someone seemed to have written as it was going along about asking the professional to check to see if an action figure had been buried in his backside.

He dons a wig and an affected manner of speaking for one weird bit with Vanessa Bayer, which may or may not have been on The Detective Channel, whose better offering was a trailer for a series about two female cops, “Dyke & Fats.” I sort of lost interest after that.

On the plus size, musical guest Sam Smith did a pretty good job for someone I had never heard of previously. With a keening soulful voice along the lines of Mick Hucknell or Roland Gift, his first song carried a punch with a melody, a full choir and a big string section. His second song, proving he didn’t need all the backing, was stark by contrast.

The only other thing that stood out was a commercial about Jos A. Bank suits being so cheap, they make good substitutes for paper towels was so weird, it worked.

Weekend Update, which was once a highlight and then a segment that offered at least something, was about as flat as I’d ever seen it. Did Seth Meyers used to write that whole thing?