Ghost prevents players from being shown on radar while an enemy Spy Plane is in the air, similarly to how UAV Jammer and Camouflage work. Ghost also brings the ability to wear ghillie suits without using sniper rifles into multiplayer.
Ghost's Pro version prevents automated killstreaks, with the exception of Dogs, from attacking the player (on the Wii version, it only protects the player from Attack Dogs). In addition, it removes the red box that marks targets for the player-controlled killstreaks such as the Gunship (Note, though, that attempting to shoot these down with missiles may expose the player to the enemy as the smoke trail is easy to spot). It also prevents the player from glowing white in the Infrared Scope or in a Camera Spike. Additionally, Ghost Pro hides the player from Tactical Mask Pro's ability to show the location of enemies the player has affected with a Concussion Grenade or Flashbang. As a final effect, the red crosshair and name do not appear when an enemy aims at a player using Ghost Pro. However, Aim Assist still targets Ghost Pro users.
Contrary to the in-game description of Ghost, neither Ghost or Ghost Pro will protect the player from an SR-71 Blackbird, Dogs (except on the Nintendo Wii version), or Motion Sensors.
Ghost returns in Call of Duty: Black Ops II, but it has been altered slightly; the player cannot be detected by UAVs while moving at a decent speed, planting or defusing the bomb in Search and Destroy or Demolition, or while using controllable Scorestreaks except for the Lightning Strike. It should be noted that the player has to be moving constantly at a certain speed across the map to be protected from a UAV; simply moving in a small circle or back and forth in the same spot at walking speed will not work. Ghost does not protect the player from an Orbital VSAT. The yellow arrow on the mini-map will slightly fade when Ghost is active.
Ghost returns as a tier one perk in Call of Duty: Black Ops III, and is unlocked at level 38. It functions identically to its incarnation in Call of Duty: Black Ops II, albeit slightly nerfed; the speed at which the player must move to keep Ghost active has been increased, preventing players from activating Ghost while crouching with any weapon or moving while aiming with assault rifles, sniper rifles, and LMGs that have a Stock attached, as well as aiming with pistols. SMGs and shotguns still keep Ghost active when moving while aiming with the Stock, but cannot do so without the Stock.
Ghost returns in Call of Duty: Infinite Warfare. It makes the user invisible to UAV. Similar to the Call of Duty: Black Ops version, it remains active even when the user is not moving. This perk directly counters UAV and Warfighter's Ping trait. It is unlocked at level 18.
After a patch, it was made that the Advanced UAV could now counter Ghost users at all times.