In its benign form, this just makes the Clueless Deputy The Watson for their boss, or the protagonist detective. But it can rapidly slide downhill until the deputy acts like an idiot. Generally, the deputy has some redeeming qualities, such as incorruptibility, shooting skills or at least the willingness to serve in a dangerous job for low pay, but if the sheriff is a Corrupt Hick, the clueless deputy may simply be a relative who needed a job.
The clueless deputy can be counted upon if the writer needs a The Guards Must Be Crazy moment to justify the heroes getting out of jail, or to act as an Obstructive Bureaucrat to keep information that could resolve the plot from reaching the sheriff.
On rare occasions, the clueless deputy of a Corrupt Hick sheriff is unaware of their superior's criminal activities, and when incontrovertible evidence is presented, will arrest the crook to preserve law and order in the county.
- Touta Matsuda in Death Note is consistently the slowest on the uptake in the investigation team. However, this naïve innocence is why he was chosen as assistant to chief Soichiro Yagami. He is also the best shot on the team, shooting Light's hands as he is about to kill Near.
- Junior Justice (son of Buford T. Justice) from the Smokey and the Bandit movies. Seriously, we're talking about a guy who refuses to keep his gun loaded because "it gets too heavy."
- Jake in the western spoof Support Your Local Sheriff, although he manages his smart moments as well. (It's more a lack of enthusiasm than his being genuinely clueless.)
- Sam Wood, in In the Heat of the Night.
- Every cop in Drowning Mona is a complete idiot, except (possibly) the Chief of Police.
- Clinton Pell, in Mississippi Burning (in physical appearance, almost an evil Barney Fife).
- Euclid Baker, in Film/Tank, a bullying weasel who also gets slapped around by his boss, Cyrus Buelton.
- Officer Lou, Marge Gunderson's assistant in Fargo.
- Norman Jonas (Jonathan Winters) in The Russians Are Coming, the Russians Are Coming.
- Officer Jong-goo, the protagonist of The Wailing, starts the movie as a fat, bumbling idiot who constantly shows up late at crime scenes, forgets to take his rain coat when it's clearly pouring outside, can't take any initiative on his own and needs to be told everything, and is so terrified by a lone, frail (though very Ax-Crazy) woman that he's completely unable to do anything to defend himself, let alone to restrain her and ends up lying on the ground, embarassing himself and all the police force at once. One of the point of the movie is to show how far he's willing to change when his family is in danger. He is still better than his own deputy, who is about as cowardly and needs to be told not to manhandle a murder weapon.
- Hank in Go West, Young Lady. At one point, he is sitting in the dancehall when he sees the sheriff go racing out in a tearing hurry. He concludes something important must be afoot and decides he should follow him. Right after the next song. General consensus among the townsfolk is that Killer Pete doesn't consider him worth killing.
- Deputy Norris Ridgewick in Stephen King's Castle Rock stories. Not only does he bear a faint resemblance to Barney Fife (his colleagues mockingly call him "Barney"), but in The Dark Half his superior actually finds it notable that when Norris discovered a mutilated corpse he had the presence of mind to face away from the evidence before throwing up. As we come to find out, "presence of mind" is not one of Norris's strong suits.
- Commander Fuzzel in Galaxy of Fear: The Brain Spiders. He's struck a deal with Jabba the Hutt, who will turn in dead criminals for the reward money, and is completely oblivious to the fact that the criminals' brains have been removed and put into other bodies, despite noticing the strange injuries.
- Barney Fife, of The Andy Griffith Show, is perhaps the paradigmatic example of this trope.
"There once was a Deputy named Fife,
- In order to make sure the audience knows that Deputy Fife is one these type of officers, the very first show has a kid scrawl this limerick on a wall to taunt Barney:
who carried a gun and a knife.
The gun was all dusty, the knife was all rusty,
'Cause he never caught a crook in his life."
- After Barney's departure from the show, the character of Warren Ferguson was introduced in an unsuccessful attempt to fill the same role.
- Festus Haggen of Gunsmoke was Book Dumb, though otherwise pretty sharp. His predecessor, Chester Goode (called Chester Proudfoot in the radio version), was a little slower-witted, although both have proven to be a Crouching Moron, Hidden Badass.
- Randy Disher from Monk. A few episodes show that while he's a good cop he simply isn't prepared to deal with the sort of cases that Monk gets. Other episodes...not so much.
- Lassie (Det. Lassiter) from Psych is a borderline case: not nearly as outrageously stupid as most of the characters listed here, he's still distinctly, and by a fair margin, the dumbest of the major characters, mostly used to provide a very easy mark for Shawn's antics. He also faces the problem of incompetent bosses.
- Deputy Perkins, of B.J. and the Bear and The Misadventures Of Sheriff Lobo.
- On Babylon 5, Garibaldi was occasionally assisted by a security guard named Jack, who came off this way, particularly when going through their investigation in the first season finale. This was because Jack was The Mole and was willfully hindering Garibaldi's investigation.
- The entire cast of Reno 911!. (Except Dangle, who's a lieutenant.)
- Gus Grimly in Fargo admits that he isn't a very good cop, and that he mostly deals with stray animals. He is much happier when he becomes a mailman.
- The Ferg in Longmire is something of a joke in the sheriff's office, as Walt employed him as a favour to his father. However, while he is not much of a street cop, the later seasons do show him to be a canny investigator.
- Deputy Andy Brennan of Twin Peaks is soft-spoken, sensitive and squeemish at violent crime scenes. He's also accident prone, simple, and often timid in confrontation. On the other hand, he's loyal as a hound, has a heart of gold and a strong sense of justice.
- Brett Mobley from Eagleheart can't read and is more often used as a club than a police officer by Marshal Chris Monsanto. It's all Obfuscating Stupidity designed to torment Chris, of course: Brett is actually Satan.
- The Misadventures of Sheriff Lobo. The eponymous Sheriff is assisted by Deputy Perkins, who is so incompetent he only keeps his job due to nepotism, and "Birdie" Hawkins, who is quite capable but a Naïve Newcomer who doesn't realise how corrupt Lobo is.
- In Nichols, the Ketchams install their cousin Mitch Mitchell as Nichols' deputy to serve as their spy and agent. However, Mitch is so dumb that he serves as just as much an impediment to their schemes as he does to Nichols' law enforcement.
- Sgt. Nails of Eagle Eye Mysteries falls most unfortunately into this category, although he's actually quite competent as an arresting officer; it's his skills as a detective that are pretty poor, as he tends to overlook certain critical clues when carrying out investigations.
- The more you play Lego City Undercover, the more you wonder how Frank Honey made it through the academy.
- Eli and Jonah from Red Dead Redemption. Jonah is profane, rude, and arrogant, while Eli is just lazy-eyed and gullible to the charms of the local Snake Oil Salesman. They're at least competent at their jobs, however (mostly Eli).
- Adachi is this to Dojima in Persona 4, mostly by saying too much and not really making the connections between the victims. As with some of the other spoilered examples above, this is because he's really the bad guy, using Obfuscating Stupidity to deliberately throw suspicion and hinder the investigation.
- Deputy Bart of Harry Potter Comics. Because Sheriff Ned is immune to memory charms, Bart's brain has been fried a bit too much from wizards hitting him in their attempts to mind-wipe the Sheriff. Bart remains effective at what he needs to do, though.
- Nutsy and Trigger in Disney's version of Robin Hood. Not that the sheriff was much better.
- Fillmore!: In the episode where Fillmore visits his old partner in Tennessee, the Corrupt Hick Safety Patrol sheriff has a Clueless Deputy who's among the few non-corrupt members of the Safety Patrol.
- Droop-a-Long Coyote was the deputy to Sheriff (ping-ping-ping) Richochet Rabbit.
- Deputy Durland from Gravity Falls. While Sheriff Blubs isn't much better, at least he learned how to read.
- Deputy Dawg. How he ever got sworn in is a mystery, although once in awhile he'll come out ahead of the swamp critters who try to outwit him.