Vincent "Vinnie" Antonelli (Martin) is a wise-cracking, flashy ex-mobster who has entered the Federal Witness Protection Program and is adjusting to suburbia with the help of Barney Coopersmith (Moranis), an FBI agent assigned to protect him, whose wife just left him for her own selfish reasons.
When Vinnie gets into trouble for committing some local crime, he gets arrested by local District Attorney Hannah Stubbs (Cusack), who is not at all happy that someone like him is being under the watch of Barney and vents at the FBI agent when they first meet. The reason for all of Hannah's frustration is because she's a divorced mom stuck raising her two sons.
But as the movie progresses, Vinnie learns to shape up, and Barney and Hannah realize their feelings for each other.
This movie provides examples of:
- Artistic License Law: Barney gets Vinny off the felony theft charge by saying that Hannah and the police had no right to search the trunk of the car without a warrant. But Vinny was arrested for car theft. As such, the "search incident to arrest" standard applies.
- Bad Liar: Vinnie is a Consummate Liar who can say anything with a straight face, but he's not always very good at coming up with the lies themselves. "Why do you need 25 copies of it?" "In case I want to read it more than once!"
- Also subverted, since Vinnie pulls off some brilliant lies with few hints at his true intentions, such as when he cons Barney into letting him off the cuffs at the airport, and especially when Vinnie insists he doesn't like guns.
- Bavarian Fire Drill: Vinnie talks Barney into handing over his wrinkled suit trousers so he can take them downstairs to get pressed, treating it as Serious Business, when his actual plan is to give his F.B.I. handler the slip. Barney stands alone in his boxers for a moment before realizing that he's been had.
- Belligerent Sexual Tension: Shown between Barney and Hannah when they first meet.
- Bilingual Bonus: Vinnie's (probably fictional) dog is named "Vaffanculo." Hannah's reaction to this indicates she not only understood it, but provides context for the audience that this was Not A Nice Thing To Name A Dog.note
- Blasting It Out of Their Hands: Despite claiming that he Doesn't Like Guns, Vinnie proves to be quite the sharpshooter when dealing with the two hit men:<hands back Barney's revolver>Barney: "I thought you said y—"Vinnie: "I Lied."
- Blatant Lies: Vinnie is pretty shameless about stating obvious lies with a straight face.
- Bunny-Ears Lawyer: Completely subverted with ADA Hannah. She searches Vinnie's trunk without a warrant, socializes with a suspect, goes back on a plea bargain, and, at the end, seems to ignore Vinnie's criminal behavior.
- She had every right to search the trunk as stated above in Artistic License Law and went back on the plea bargain because there weren't any criminals there. Vinny was wrong and didn't help the DA's office so the deal is off.
- Character Development: Vinnie becomes more responsible and it's implied he really does come to love and care about the town. Barney loosens up and learns to enjoy his life; Hannah does the same.
- Comedic Underwear Exposure: Happens to Barney when Vinnie rebels yet again while they stay at a New York hotel.
- Crapsaccharine World: The mobsters in Witness Protection feel this way about Fryburg. Vinnie's testimony at trial sums it up:"I get to live in a place - it's okay, don't get me wrong - the air is clean, the people are nice; but for a guy like me, who was raised on the sidewalks of the city that never sleeps, it's a living hell."
- Creature of Habit: Barney starts as this, to the point that his wife leaves him because he never changes anything about his routine and is not fun anymore.
- Disgusting Public Toilet: Vinnie doesn't like to use public toilets as shown in two scenes.
- Distracted by the Sexy: Vinnie in the grocery store when he sees Chaldean.
- Embarrassing Nickname: While undercover as someone from Vancouver, Barney is unfortunate enough to get the nickname of "Dicky", much to his dismay.Barney: Call me "Dicky" one more time, and I'll kill you.
- Even Evil Has Standards: When Vinnie's put on the stand, the cross examination tries to discredit him by pointing out all the perks of being in Witness Protection. Vinnie then continues by pointing out he also never gets to see his parents or friends again and that his wife left him. He finishes by saying it's true that he's only saying these things because of the government deal — but he gave his word that he'd tell the truth, and that's what he's doing.
- Of course since Vinnie is a Consummate Liar, you have to take everything he says with a grain of salt.
- Everyone Chasing You: The movie's climax following the escape from the courtroom.
- Fake-Real Turn: Vinnie gets bored with life as a suburbanite, so he begins a scam that involves getting donations of loose change to "renovate the little league park." At first he plans on just pocketing the money and getting out of town. By the end of the movie, not only does the local little league team have a new place to play, Vinnie is coaching them.
- Foreshadowing: Hannah insists that her town is not the dumping ground for the FBI's criminal elements. She has no idea how wrong she is.
- Here We Go Again!: The pair of hitmen sent to kill Vinnie end up in Witness Protection as well. They even live in the same town and have married Vinnie's first and second wives.
- Karma Houdini: Vinnie is a criminal who has no real remorse and continues to commit crimes on a daily basis... and is voted the Man of the Year.
- Lightbulb Joke/So Unfunny, It's Funny: "What's the difference between a light bulb and a pregnant woman? You can unscrew a light bulb."
- Marry Them All: Vinnie has three wives over the course of the movie. And not a single divorce (that is seen or mentioned, at least).
- Mugshot Montage: As Vinnie poses for his new ID photos, he reassures his handler that "this isn't the old me, this is the new me", while unconsciously posing as if he were having his mugshot taken.
- Running Gag: Barney never seems to remember to unfasten his seat belt before trying to get out of the car. On the 3rd and final time, he becomes aware of this habit.
- Sharp-Dressed Man: Vinnie loves his shiny suits, and makes sure Barney gets one, too. His Little League coach's outfit is even a nice suit in the team colors, complete with baseball pinstripes.
- Straight Man and Wise Guy: Barney and Vinnie
- Super OCD: Barney is implied to have this, particularly when he eats pancakes.
- Titled After the Song: With Fats Domino's version appearing on the soundtrack.
- What Happened to the Mouse?: Despite the mob now knowing where Vinnie and many other ex-mobsters live, no one is moved and the assassins are there as well.
- Witness Protection: The whole premise is how much trouble Vinnie has in dealing with the new lifestyle required by the program. There are some technical inaccuracies (including the FBI running the program rather than the US Marshals), but they don't change the premise.