Ned Fleming (Bryan Cranston) goes on a trip with his wife and teenage son to visit his daughter Stephanie (Zoey Deutch) at Stanford over the Christmas holidays, only to have to deal with (and suffer) her boyfriend, Laird Mayhew (James Franco), a very eccentric and very socially awkward Silicon Valley billionaire.
Tropes include:
- Abusive Parents: From what is mentioned by Laird, his mother was an abusive Stage Mom.
- The Ace: Laird has almost everything going for him, such as money, career, and looks, but is still off-putting to Stephanie's parents due to having No Social Skills and no boundaries.
- A.I. Is a Crapshoot: Justine comes with her own attitude, is overly sensitive and talks back at humans if they don't respond to her in a calm tone. She's also too meddling in Ned's personal life as she becomes more of a bother than an assistant.
- Benevolent A.I.: Nevertheless, she can be pleasant-ish enough, as long as they do not raise their voice and remain patient with her. Plus, it's clear she means well but probably isn't programmed well enough to convey it, much similar to her creator's lack of social skills.note
- Annoying Younger Sibling: Downplayed. While Scotty makes a few inappropriate comments regarding Stephanie and Laird's relationship, he's not overly obnoxious and comes to like Laird.
- Ascended Fanboy: And fangirls. In an attempt to propose to Stephanie, Laird invited KISS. Needless to say she, her family, and their guests are shockingly, but pleasantly pleased.
- Bittersweet Ending: Heavy on the sweet side—Stephanie declines Laird's marriage proposal, but it's only because she's not ready quite yet and still wants him as a boyfriend. Thanks to Scotty's idea and Laird's production, Ned's company is saved. Plus, Laird has the family he always wanted.
- Calling the Old Man Out: Stephanie does this to Ned for not giving Laird a chance and even trying to get information about Laird to show he's not a good guy.
- The Cameo: Tobuscus makes a cameo in the film.
- Cloudcuckoolander: Laird is a sweet, if slightly eccentric man.
- Cluster F-Bomb: A lot of f-bombs are dropped in the movie, mainly from Laird.
- Daddy's Girl: Ned and Stephanie have a very close relationship. It's even lampshaded at Ned's birthday party in the intro.
- Dance Party Ending: Liard and Stephanie, and the Flemings, are shown dancing at a Christmas party before the film cuts to the credits.
- Dark and Troubled Past: Laird mentions that he never knew his father and his mother was an awful parent.
- Disappeared Dad: Laird mentions that he never really knew his father.
- Everyone Has Standards: Laird has no filter and says some pretty inappropriate things, but even he's exasperated and partially disgusted by Tyson Odell's vulgarity, who seems to have even less of a filter than Laird does, which is saying something. Laird even agrees with Stephanie when she says that Tyson is 'the worst'.
- Freudian Excuse: A big part of why Laird does extravagant (if ridiculous) acts to impress Stephanie's family is because he always wanted a family since he didn't have one as a child.
- Funny Background Event: Laird dropping his pants behind Stephanie during her Skype chat with her dad at his birthday party.
- I Gave My Word: Laird promises he won't propose to Stephanie without Ned's blessings. He stays true to his word even when Stephanie is upset at Ned for spying on him.
- Genius Ditz: At first glance, Laird is a childish Cloudcuckoolander—but he did make his own company, is interested in numerous foundations, and later proves to be a genius when it comes to detecting hackers. He also knew how to invest his profits so he's still a multi-millionaire in spite of his company's bad phase.
- Gold Digger: Discussed. The reason Laird initially didn't tell Stephanie about his fortune when they were dating was because he had to make sure she wasn't after his money.
- Groin Attack: During a fight with Laird, Ned bites his groin.
- Heterosexual Life-Partners: Gustav and Laird are each other's best friend and confidante.
- Innocently Insensitive: Laird means no harm, but has a tendency to curse and reveal things that are better left discussed not by him.
- Manchild: He's ten years older than Stephanie, but Laird acts as if he's still Scotty's age (15) or younger.
- Nice Guy: Laird may be weird at times, but he's a genuine sweetheart.
- "Not So Different" Remark: Lampshaded by Stephanie, who tells Ned that Laird is the man who reminds her the most of him, in the sense that he's completely honest, with no filter.
- No Antagonist: There's really no one who acts as "villain" of the film. Even Ned attempting to find evidence that Laird isn't a good guy is ultimately just out of concern for his daughter.
- Not This One, That One: When Ned and Laird go to a Christmas Tree shop, Ned looks at what he believes to be the christmas tree Laird chooses and likes it. However, the tree Laird chose is serving as a decoration at a nearby building.
- Porn Stache: At the start, Stephanie states that Laird needs to shave his "porn stache".
- Questioning Title?: Why Him? is about a father who questions his daughter's decision to date a "bad boy".
- Shipper on Deck: Gustav belies that what Laird and Stephanie has is truly special.
- Shout-Out: When Ned first sees Laird and Gustav's training sessions, he compares it to Clouseau and Cato in The Pink Panther series, and is surprised when the two genuinely don't know what he's talking about.
- Single Woman Seeks Good Man: The reason Stephanie loves Laird is because she reminds him of the positive qualities of her father - Honest and caring.
- Stacy's Mom: Laird even says that Barb is a total MILF.
- Trailers Always Lie: Although a crucial part of the movie's first trailer, Laird never sicks a spy drone upon Ned and Stephanie. And there's no rock-hurling incident.
