With his troublesome heart condition, Stark wanted to create a cheaper, scaled-down version of Iron Man, to be used as a back-up; He based the armor's design loosely on his then-current MK IV Armor, only without many of the extra details (Perhaps most notably the anti-gravity pods on each hip and the "cuffed" gloves and boots); Making it very sleek and form-fitting. The helmet was similar to the Iron Man armor only without the mouth section, and a "less human" face compared to Stark's own armor. A flaw in the cybernetic control of the original design led to the original user, Stark's friend Kevin O'Brien, being driven insane. In his unstable condition Kevin soon became a pawn in Simon Gilbert's attempts to oust Stark from his own company. Stark was forced to don his Iron man armor and fight the Guardsman. Stark defeated the Guardsman, who tried to take refuge in an experimental tank. Stark tried to stop him without injuring him, so he shot the tank, and accidentally hit the fuel depot. The tank exploded and killed O'Brien. 
When Kevin died, it appeared that the story was finally over. However, several months later the vacant armor was discovered, stolen and donned by O'Brien's brother, Michael, an NYPD sergeant who wanted to get revenge on Stark and Iron Man, although he later decided that Iron Man was a hero and had no choice but to kill Kevin to save lives in danger. Michael O'Brien retained the armor (once the flaw was removed) and became security head for Project: Pegasus.
The armor was later put back into production by Stane International. Stane sold number of armors to the Vault for security. Oddly enough, Michael O'Brien was now security head for the Vault. During the first Armor Wars, Stark was forced to use his negator packs to destroy the 41 known armors assigned to the Vault. Afterward, Stane International (by now under the control of Justin Hammer) built replacement armors, but without Stark's Iron Man technology, they were markedly inferior to the original suits. Stark Enterprises later entered into an agreement with the United States government to replace the Stane suits with superior new models, with security safeguards in place to prevent their misuse.
Edwin Cord produced modified versions of the Guardsman armor for the Jury.
The armor only had the basic capabilities of the Iron Man armor. It could fly, fire repulsors, and had limited life support. It enabled the user to lift roughly 40 tons. The armor was powered by a thermoelectric generator and had a 500 watt chemical battery as a secondary power source. Flight was attained through chemically fueled boot-jets that could reach 250 mph and would allow a lift capacity of 1,500 lbs. It was vastly superior to Stark's original armor, being faster, sleeker, more lightweight, as well as overall more efficient. Despite being loosely based on Stark's MK IV armor in terms of appearance, Tony made sure not to make the Guardsman armor his equal.
The current version of the Guardsman armor had a bulkier frame and was outfitted with mounted guns on the shoulders.
Though many people have borrowed or stolen Stark's technology over the years, the Guardsman armor marks one of the few times Tony Stark built a suit of armor meant for someone other than himself. Other examples include the Silver Centurion armor he created for James Rhodes (but ends up keeping it for himself), the War Machine armor (which Rhodes does wear), and the Iron Spider armor which Stark created for Peter Parker.
- 90 Appearances of Guardsman Armor
- 5 Minor Appearances of Guardsman Armor
- 3 Media Guardsman Armor was Mentioned in
- 10 Images featuring Guardsman Armor
- Item Gallery: Guardsman Armor