The ghost hunter profession is introduced in The Sims 3: Ambitions. Sims use various machines to trap or ward off ghosts, similar to the Ghostbusters film franchise, and the Nintendo GameCube game, Luigi's Mansion as well as its 3DS and Nintendo Switch sequels.
Ghosts and lesser spirits will randomly appear in occupied houses around neighborhoods. These ghosts range from small, floating cartoon ghosts to regular Sim ghosts.  Ghost hunters must deal with several different types of investigations and paranormal activity in order to advance.
Types of paranormal activity
Lesser spirits are the weakest form of paranormal activity. Lesser spirits resemble wispy Halloween ghosts. They come in many colors, which represent their personality. Certain personalities are more valuable than others. For example, white spirits (who have a friendly personality) aren't worth much to researchers while orange spirits (who are wrathful) are worth more.
Spirit colours and types:
Lesser spirits can also be collected and named like beetles and butterflies. They can even be transfigured, which will produce a tombstone with a normal ghost.
The player's Sim can also try to collect spirits from any places at any time using the Spook-O-Meter to make them visible, which apparitions should have been detected by Spirit Positioning Device. (To get the Spook-o-Meter a Sim needs to be level 5 in this career)
Poltergeists possess random objects, causing them to move and fly around. Poltergeists are not very powerful, but they are stronger than lesser spirits.
Ghosts are the most powerful of all paranormal activity. They are very hard to capture, but ghost hunters may alternatively attempt to befriend a ghost and convince them to move on.
Occasionally, ghost hunters may encounter ghosts from past civilizations. These ghosts are worth more money when sold to the science lab.
Types of investigations
Spirit invasions are the most basic of hauntings. Lesser spirits are much less powerful than full bodied ghosts, and are visible at all times. Ghost hunters need only use the banshee banisher to remove the lesser spirits. If the spirit manages to escape the ghost vacuum, they will scare any non-brave sim.
Occasionally, a ghost hunter will be asked to investigate a random rabbit hole. The ghost hunter need only enter the venue and stay for a few hours to complete this investigation.
During a poltergeist haunting, the ghost hunter must exorcise furniture that is being possessed by poltergeists.
If a Sim has the kleptomaniac trait, they will not discriminate between possessed and normal objects.
If they swipe a possessed object, it will no longer be haunted after it has been placed into their inventory, even if it is later returned in the mail. However, this cleansing will not count towards the required exorcism count, rendering the mission incompleteable. There is a chance that this same mission will now be offered every future evening. The (incomplete) progress will be saved, rendering this particular exorcism mission permanently incompleteable.
During this investigation, ghost hunters must find and remove a full bodied ghost. To find the ghost, the ghost hunter must scan rooms of the house with the Spook-O-Meter (similar to the Ghostbuster's PKE Meter). After the ghost has been located, the ghost hunter can attempt to capture it. Alternatively, the ghost hunter may befriend the ghost and convince them to pass on.
Angry ghost invasion
This is similar to the previous job, but ghosts are visible from the start. They are scaring Sims and using house appliances. There will also be frightening background music during the exorcism.
Apart from that, this job is the same as above. Actually it is easier, as the ghost hunter doesn't have to spend time searching them.
- Spooky Trophy (Honor Trophy): Capture 15 Spirits
- Ghost Hunter's Paranormal Medal (Hero Medal): Capture 75 Spirits
- Ghost Hunter's Bravery Ribbon (Award Ribbon): Capture 150 Spirits
- Ghost Hunter's Spirit Medal (Epic Hero Medal): Do 7 Paranormal Investigation Case
- Ghost Hunter's Key to The Town: Reach Level 10
- Paranormal Momento: Capture 25 Spirit after reach level 10
- Some ghosts share the same last name as some historical figures, such as Juliette Antoinette who shares the same middle name as Marie Antoinette.
- Two more examples are "Napoleon Amoit" and "Touissant Bonaparte", obvious references to Napoleon Bonaparte.
- It is possible to use testingcheatsenabled to add the ghosts from the Profession to the Household. After they are saved to the Library, they can be played as usual.
- SimBots can be useful in this profession since they start with the brave trait as they are not scared by ghosts but Humans and Vampires with the brave trait are also useful in this profession as they won't be scared by ghosts.
- Vampires would especially benefit since it's one of the few jobs done at night.
- If a Sim does an inappropriate action while doing a job, it will say a different message rather than the Sim's name is behaving inappropriately! If he/she continues, I will have to ask him/her to leave. that is usually displayed while visiting. However, it will be displayed if a such action is done after the job is finished.
- Ironically, a ghost may have a wish to join the ghost hunter profession even though the profession is about catching ghosts.
- There are obvious references to Ghostbusters in this profession. The object used to capture ghosts resembles the Proton Beam (albeit without the backpack) and the first uniform the Sim receives has bright green stains on it, likely a reference to the Onionhead (Slimer) ghost from the films. Coincidentally, a firefighter profession is also included in Ambitions, so it is possible for ghost hunters to reside in a firehouse.
- When releasing a collected ghost sometimes a semi-rare dialogue box will appear with 'Thanks for releasing me, <Sims Name>! Its nice to be out of that Jar. I'm going to move in with <townie's first name>, theres [sic] plenty of room for both of us.'. The Sim mentioned by the Ghost is randomly generated, as there is no evidence of the Ghost living at that Sims house if you visit with one of your Sims, even when the grounds are scanned with the Spook-o-meter.
- Rarely, or perhaps just in Moonlight Falls, a ghost hunter doing a Ghost mission will be unable to see the ghost, even after they discover which room the ghost is located in. The mission will be impossible to complete. This is also true for any other towns as well. There are two solutions to this problem: 1. Pause the game until the ghosts render (approximately one to five minutes) or 2. Send the Sim to the lot but don't assist them.