The Ghost Suit was built by S.H.I.E.L.D., who had been told of the case of Ava Starr, a young girl who suffered from molecular disequilibrium, causing her to randomly phase in an out of the reality, thus giving her intangibility powers. Since Starr had trouble controlling these powers, S.H.I.E.L.D. gave her the suit and trained her so she could master these powers, which they then used to weaponize her. Armed with this suit, Starr became a formidable S.H.I.E.L.D. operative and carried on numerous missions.
When S.H.I.E.L.D. fell due to the HYDRA Uprising, Starr, now known as Ghost, kept the Ghost Suit and was reunited with Bill Foster, who promised to do anything he could to cure Ghost from her condition. Upon learning about Hank Pym's efforts to bring his wife Janet van Dyne out of the Quantum Realm, Ghost saw it as an opportunity to be cured. During the Battle at the Oui, she confronted Wasp, using her suit's capabilities to phase out and avoid Wasp's attacks. When Ant-Man intervened, Ghost left and instead faced Pym, phasing her arm through his neck and threatening to kill him, thus successfully obtaining the Mobile Laboratory she was after.
Returning to her hideout, Ghost took off her suit to enter her Quantum Energy Chamber and get some rest. The suit was later found by Ant-Man as he infiltrated the place. Although Ghost and Foster managed to capture Ant-Man, Wasp and Pym, Ghost was not able to put her suit back before they escaped. She then used the suit to infiltrate into the X-Con Security Consultants Office and learn the location of the Mobile Laboratory from Luis, before heading to Muir Woods and using the suit's phasing to kill FBI Agent Stoltz and stealing the lab.
The suit's capabilities were once again used with proficiency by Ghost during the Chase for the Mobile Laboratory, although the helmet was damaged by Giant-Man, causing the control of the phasing to be more difficult. Still, Ghost was able to steal the Mobile Laboratory and to enter it in an attempt to absorb quantum energy from van Dyne who was returning from the Quantum Realm. However, Ghost was eventually defeated by Ant-Man and the Wasp, and the Ghost Suit sustained many damages which led to Ghost randomly phasing again.
The Ghost Suit could later be discarded as Ghost was able to be cure from her molecular disequilibrium thanks to direct quantum energy transfers which stabilized her.
The suit covered the entirety of Ghost's body. Whereas her phasing appeared to be random and uncontrollable when she was not wearing it, the suit enabled Ghost to phase in an out at will, which in turn gave her incredible intangibility abilities. She could thus infiltrate through any building by simply phasing through the wall, regardless of how thick it could be. She could also phase through flesh, meaning that she could cause lethal wounds by simply touching another human being. The phasing also allowed Ghost to become invisible by phasing out of the visible spectrum, as well as increasing her physical strength whenever necessary. However, the more damage the suit sustained, the more difficult the control of the phasing became.
According to Ghost, the suit was also supposed to reduce the incredible pain she was suffering from, but actually did not do much in this regard.