Normally, it's seen as a good idea to get someone skilled to perform a job. If your car or house needs repair and you don't have those skills, Step One is a phone call to a repairman.
But sometimes the person you hire isn't as skilled as you'd expect a professional to be. The carpenter putting in your deck doesn't bother to make it level. The mechanic working on your car decides he doesn't need the correct part, he can make something in his shop "fit". No matter what the specific job, the one thing characters who fall under this trope have in common is that they can't note do the job they were hired for. This character might be a Con Man, or he might have a higher regard for his "skills" than anyone else does. Sometimes the man is a veteran expert in whatever field of work the plot requires, but the moment it's pointed out that it needs someone running on "best expert in the world" levels of expertise, then anybody else instantly becomes this trope.
Distinct from Doom It Yourself and D.I.Y. Disaster in that those tropes involve amateurs attempting tasks in which they are untrained, and this trope applies to people who are (supposedly) trained and (purportedly) do for a living. Can sometimes be caught via Spot the Imposter.
Shares the same general competence level as The World's Expert on Getting Killed. The main difference is that the Alleged Expert usually gets fired or sued, not killed. If the job involves operating a vehicle, this can overlap with Captain Crash.
- Les Tuniques Bleues has a former Southerner who moved to Canada to mine gold bequeath his fortune to the South, with our heroes sent to stop him. They also hire a coureur des bois to guide them, and every time Chesterfield cites a Memetic Badass-level fact about them, the guy proves him wrong (falling flat on his face every few feet, giving them fleas, leaving clothes on anthills to get rid of parasites and getting them back full of ants). When they finally reach the prospector's cabin, they find the Southern delegation... who it turned out hired the guide's equally-inept brother. The prospector dies of laughter after explaining the guides had only just gotten out of the forest from that cabin after several months (a few days' trip), and it turned out he'd only ever mined a few ounces of gold.
- A brief gag in the live-action Casper film has the baddies hire Ray Stanz from Ghostbusters to remove the ghosts, but he is unable to do it.
Ray Stanz: Who you gonna call? Someone else!
- The "exorcist" that was hired before him (Father Guido Sarducci) was an even better example of this trope: his "training" in how to deal with the supernatural came from a video correspondence course. He comes out of Whipstaff Manor five seconds after going in, with his head twisted 180 degrees backwards (yet still acting fine).
- Spence in Ronin is supposedly an ex-SAS trooper turned mercenary brought in to provide firepower for the team. In the first firefight (and immediately later on when proposing a real piece of high-risk Hollywood Tactics for the heist) he is exposed as a fraud and dismissed from the team.
- Subverted in My Cousin Vinny. The Public Defender assigned to the case turns out to be the "bumbling professional," and should have caused the judge to call for a more experienced lawyer; meanwhile Vinny wins the case despite never having worked as a lawyer.
- A staple of The Three Stooges shorts. Piloting, plumbing, home constructing, engine repair, medicine, espionage, cooking, painting, training, advertising, artillery gunnery, banner gluing, liquor brewing, census taking, babysitting, baggage handling, photography work, science work, detective work, sheriff work, leading a freaking country, you name it — they are a Walking Disaster Area in each and every field and will bring humiliating destruction to anybody dumb enough to hire them.
- The contractors from The Money Pit are a subversion. Despite their slapdash approach and colourful personalities, they do manage to do a good job of more or less rebuilding the eponymous Pit.
- Killer Elite has a downplayed example. Hunter is still a dangerous fighter but due to his age and lack of resources he is no longer capable of pulling off the assassinations he was hired to do.
- The core of the plot of MouseHunt focuses around 2 brothers who inherit an old house, but try everything they can think of to get rid of a little pesky mouse. Eventually they have to hire Caesar, a professional exterminator who NEVER gives up until the job is finished, even if his methods are more than a tad crazy. After using everything in his arsenal and every trick in the book, even he's not able to get rid of the mouse.
- Played for Drama in Munich. One of the team members is supposed to be a bomb maker, but every device he builds is faulty in some way. Eventually, he reveals that he was actually trained as a bomb defuser, and only agreed to try his hand at building them when asked to by Mossad following the Munich attacks.
- Harry Potter and the Chamber of Secrets: Gilderoy Lockhart was hired as the new Defense Against the Dark Arts instructor due to his track record of defeating magical monsters. It turns out that his only real skill is stealing the credit for those defeated monsters from the witches and wizards who actually did the work. That, and Memory Charms.
- Discworld has "Bloody Stupid" Johnson, an architect and inventor who was so incompetent that some of his designs broke the laws of reality. For example, he designed Empirical Crescent, which looks like a normal upper class neighborhood until one discovers that inside the front door of No. 1 opens into the back bedroom of No. 15, among other impossibilities. At one point, he was in high demand among the nobility, becuase it was seen as a mark of someone's wealth that they could afford to waste their money on something he made.
- Holmes on Homes is all about fixing the aftermath of this.
- The Monroe brothers on Green Acres are supposedly the best contractors in Hooterville, yet they make an absolute mess of remodeling the Douglases' home. Justified in that before then they were only building chicken coops (which is exactly what they build the very first day on the job).
- One episode of Reno911 had the Reno sheriff's department bring in an FBI profiler to help them with a case. The profiler, however, turned out to be even more incompetent than the deputies usually are.
- Barry Zuckercorn from Arrested Development is a lawyer, but not a very good one. He routinely gives out poor legal advice and at one point has to look up something at Ask Jeeves. His advice even gives Michael some unneeded angst in the pilot when George puts Lucille in charge of the Bluth Company instead of him.
George: Michael, the SEC has been after me for years. If I had put you in charge, you'd be in here wearing one of these orange jumpsuits yourself. You'd be an accomplice! (beckons Michael closer and whispers) The deal is they can't arrest a husband and wife for the same crime. Get it?Michael: Actually, that's not true, dad.George: It's not?Michael: No.George buries his face in his hands.George: I've got the worst fucking attorneys.
- On Community, it seems to be par for the course for Greendale Community College to assign teachers to a course they know nothing about. In season one, Chang admits he doesn't know how to speak Spanish and isn't credentialed as a Spanish teacher. (He gets fired as a result.) In season two, Professor Duncan is assigned to teach Anthropology which he immediately admits he knows nothing about.
- Fallout: New Vegas has Fantastic, a technician hired by the NCR to fix the power grid at Helios One, who has absolutely no idea what he's doing.
Fantastic: They asked me how well I understood theoretical physics. I said I had a theoretical degree in physics. They said "Welcome aboard."
- An optional side quest is to fix the grid yourself. If you do, Fantastic will end up with full credit for the work and may (depending on how you did in the quest) be promoted.
- Garrus Vakarian in Mass Effect 3 was appointed by the Turian Hierarchy as their "Reaper Expert" to assist in the war against them, a position he is not to happy with given how limited his (and Shepard's) knowledge about the Reapers is; however it's actually subversion, since considering Garrus' adventures with Shepard fighting the Reapers in the previous two games, there's no other live Turian with the knowledge and experience (limited as it is) that Garrus has.
- Belkar was invited to join The Order of the Stick on the grounds that he's a ranger, and Roy assumed that he had some skills as a tracker. Belkar later reveals that he hasn't invested a single point in his track skill, and only took the class because it lets him dual wield knives.
- Marina from Crystal Heroes claims to have used to be an adventurer (in the D&D-style hired RPG party way), but when the party gets into their first real fight in the dungeon, she freezes up completely out of fear. Afterwards, it's revealed that Marina never actually was part of an adventurer party in the past. She did travel around with them, but only did domestic tasks for them instead of helping fight.
- Rinkworks' Computer Stupidities section has two whole pages for these: one for incompetent tech support and one for incompetent salesmen. The miscellaneous page has a few examples of incompetent computer teachers.
- In King of the Hill, this is one of the show's most frequent recurring plotlines. Generally speaking, so-called experts come in two flavors: a truly villainous so-called expert who has not been stopped because either nobody else truly knows better or doesn't wants to go against the crowd, or someone who is genuinely talented and honest but so incredibly quirky that it's hard to tell.
- Hank's house tests positive for mold right before a big homes tour. It turns out the mold inspector is just dragging his feet to squeeze more money out of the insurance company.
- The first episode has a plot wherein some social services guy tries to take Bobby away without bothering to do any actual research on his home's status. When the proper research is done, the first guy gets fired. The same man appears later enforcing a disabled workers' act that forces Strickland Propane to hire a completely incompetent junkie and allows him to run roughshod on the office).
- In the Rocky and Bullwinkle storyline "Rue Brittania", Boris has a job as an exterminator, and is hired by the nephews of the deceased Earl of Krancase (who get Bullwinkle's inheritance if he dies) to exterminate Bullwinkle. After a number of failed attempts, Boris offers to pay them to kill Bullwinkle. When one says that he thought Boris was an expert, Boris says that he is an expert "at not killing moose!"