Mike O'Donnell is the star of the high school basketball team, his girlfriend is the hottest girl in school, and he's about to be offered a scholarship. But his life takes a turn for the worse after he discovers his girlfriend is pregnant.
Flash Forward twenty years, and his life hasn't improved. His wife has kicked him out, his kids hate him, he's just been fired, and he's living with his geeky but much richer best friend. After going to his old school to pick up his kids, Mike is approached by a mysterious janitor whom he tells that he'd do anything to relive the Glory Days. On his way home, Mike sees the same janitor about to jump off a bridge. Rushing to save him, he topples over the edge and lands in a whirlpool.
When he crawls out and gets back to his friend's place, Mike discovers he's been turned into
Zac Efron his 17-year-old self. Now he has a chance to sneak into the lives of his family and get another chance at the life he wanted.
- Adorkable: Alex.
- Aesop Amnesia -- The girls who are impressed by the abstinence speech Mike gave to their class still try to seduce him later in the movie.
- All Guys Want Cheerleaders -- Averted. Neither Scarlet nor Maggie are cheerleaders despite the fact that they date the captains of the basketball team in their respective decades. The actual cheerleaders appear to be Mike's pals and/or background dancers.
- But then of course there's Alex who does want a cheerleader, and actually gets her.
- Almighty Janitor -- With a title like 17 Again, it was inevitable.
- Aw, Look -- They Really Do Love Each Other -- Mike finally proving to Scarlet who he is and that everything he has done was to help his family.
- Book Ends -- Mike is playing basketball, Scarlet walks into the room, he resumes playing basketball, she starts to leave, he abandons the ball and chases after her. The parallel plays out up until the dramatic twirl, when he strains his back and has to put her down.
- Bratty Teenage Daughter -- Maggie.
- Brainless Beauty -- Most of the girls who chase after Mike literally have no respect for themselves.
- Closet Geek: The principal.
- Daddy's Girl -- Subverted.
- Digging Yourself Deeper: Happens quite often with Mike.
Mike: [Absent-mindedly] You're an excellent dancer.
Scarlet: Excuse me?
Mike: [Backtracking] Uh... I mean... you look like you can really move. [Barely refrains from facepalming]
- Distracted by the Sexy: Scarlett's first run in with 17-year-old Mike. She's so dumbstruck over how much he looks like a younger version of her husband that she ignores her friend's advice to stop acting like a fool. She eventually has to be physically stopped from going over to smell him.
- It helps that she's also quite drunk, having just returned from a "happy hour" with her friend.
- Double Standard: Remember all those funny scenes were Scarlett's trying her best not to ravage the teenage likeness of the man she loves, while he's practically seducing her, and all the sexual undertones between them? Yeah, now imagine if it was Scarlett who got turned back to 17. One can only imagine the moral outrage if it featured a middle-aged man lusting after a teenage girl.
- The Eighties -- Mike was 17 in 1989.
- Fountain of Youth -- The basic premise.
- Geeky Turn On -- After trying lavish schemes to win over the heart of Mike's new principal, Ned finally captures her heart when he speaks Elvish to her... and she replies in the same way.
- Genre Savvy -- Ned. Particularly strong when he tries to figure out what triggered Mike's transformation.
Ned: Are you now, or have you ever been, a Norse god, vampire, or time-traveling cyborg?
Mike: You've known me since, what, first grade? Maybe I would have told you.
Ned: Vampire wouldn't tell... cyborg wouldn't know.
- Gilligan Cut: When Mike convinces Ned to pose as his dad and enroll him in high school. Used in both the movie and the trailer.
- Hey, It's That Guy!: Chad Dylan Cooper as an awkward, bullied nerd.
- Hey, It's That Voice! -- The janitor is friggin' Captain K'nuckles and The Flying Dutchman.
- High School Hustler - Mildly deconstructed with Mike.
- Jerk Jock -- Maggie's boyfriend, Stan.
- Likes Older Women: How 17-year old Mike tastes look to his son.
- Mistaken for Gay -- Maggie concludes that (17-year-old) Mike is gay after he is obviously squicked by her advances.
- Overprotective Dad -- Mike. Hell, one of his attempts to protect his daughter ends up on Youtube.
- Papa Wolf -- Mike again. Don't make fun of his son while he's watching.
- Parental Incest -- Mike's daughter falls for him briefly, but thankfully it goes no further than that.
- Kissing Cousins: Tecnically.
- Parents as People -- Justified by the fact Mike and Scarlett were both teenage parents, and unprepared to deal with raising kids. Mike needing to get over this is the whole point of the movie.
- "The Reason You Suck" Speech -- Mike gives one to Stan the first time they talk, utterly annihilating him in front of the entire lunchroom. It begins with a Stealth Insult, followed by three cited Freudian Excuses for Stan's Jerk Jock personality (Armoured Closet Gay, Book Dumb and Compensating for Something) and ends with a Stepford Smiler.
- Shout-Out -- Ned has a shoutout moment during the scene when he mistook the newly transformed Mike for a thief.
Mike: Ned, I'm telling you, I'm telling you: stop it. Stop it. Now.
*Picks up a lightsaber*
Ned: Oh..an elegant weapon. From a more civilized time.
*Ignites his lightsaber*
- Two entire scenes are shout outs to classic movies:
- Back to The Future - when Mike wakes up after taking a punch from Stan in his daughter's bed and recounts the events so far as a horrible nightmare he had, only to realize it wasn't a dream and his daughter is hitting on him.
- It's a Wonderful Life - Mike is tricked into the magical whirlpool that turns his age back when he sees his "spirit guide" apparently committing suicide off the bridge.
- Two entire scenes are shout outs to classic movies:
- Stacy's Mom -- Subverted, but that's what he claims when his son catches him talking about her.
- Set Right What Once Went Wrong -- Subverted. He thinks this is what he is supposed to do but finally, he makes the same decision which he did 20 years earlier.
- Shirtless Scene -- The opening.
- The Talk -- Mike gives an abstinence talk in health class. Ironically, it would have been even more effective if he was an adult, as he is a poster boy for what happens to your life because of teen pregnancy.
- That Was Not a Dream -- In a Shout-Out to Back to The Future, Mike deliriously tells his daughter that he dreamed he was 17 again.
- Trust Password -- Subverted. Mike gives several to Ned when trying to prove his identity, and Ned gives reasons why each one could've been faked. It takes looking at a picture of them both during their high school days to convince him.
- Unwanted Harem -- Several school girls for Mike and eventually, his daughter and his somewhat confused wife.
- Wet Sari Scene -- When Mike returns home and looks in the mirror, he sees his seventeen-year-old self completely soaking wet... and wearing a complete suit.
- Wild Teen Party
- You're Not My Father -- After Mike forbids Maggie from moving in with Stan.