The Mark IV Armor was Tony Stark's fourth Iron Man suit and was built to replace the Mark III after it was heavily damaged in Stark's fight with Obadiah Stane. Because it was built to be a direct replacement, the Mark IV is very similar to the Mark III with only a few minor changes.
After the Mark III suffered irreparable damage in Stark's battle with Obadiah Stane's Iron Monger Armor, Stark built the Mark IV suit to replace it, becoming the primary suit that Stark used in all of his activities as Iron Man. During the Stark Expo, Stark air-dropped to the main presentation stage in the Mark IV suit to make a grand entrance and give the opening speech, sporting a tuxedo underneath the armor.
Due to the stress of slowly being poisoned by the palladium in his Arc Reactor, Stark got drunk while wearing the Mark IV armor at his birthday party, believing it may be his last, and put several of his party guests in danger. Concerned about the safety of the party guests and the controversy an incident may cause, Stark's friend Lt. Colonel James Rhodes donned the Mark II suit and intervened, ordering the guests to leave and for his friend to desist in his reckless behavior. Stark and Rhodes then engaged in a fight through Tony Stark's Mansion, which ends with Stark being narrowly outmatched and Rhodes taking the Mark II for the Military.
Tony Stark was later seen wearing the Mark IV the next morning while grabbing doughnuts at Randy's Donuts, eating while sitting in the eatery's large, signature doughnut sign, where he was approached by Nick Fury.
When Stark's mansion was attacked by the Mandarin, the Mark IV is destroyed when damage to the mansion's systems caused the suit to unintentionally detonate (possibly due to an overload of the miniature arc reactor).
Made to serve as a direct replacement for the damaged Mark III armor, the Mark IV carries over many of the same capabilities and functions, while only making a handful of advancements.
As with the previous suits, the Mark IV enhanced the user's physical capabilities, granting them superhuman strength, near bullet-proof durability, and enhanced movement, speed and reflexes. The suit also carried over the repulsor technology, allowing for sustained flight while also serving as the suit's main weapon along with a greatly improved uni-beam.
The Mark IV also carried over the other weapons systems present in the former suit, including: multi-fire, computer targeted mini-guns in each shoulder, high explosive, anti-tank missiles housed in each forearm, and non-weaponized flairs contained in two circular launchers located at the suit's hips.
However, even while retaining most of the previous specifications, Stark was able to improve various details of the suit's visible design such as the suit's internal mechanics as well as the design of the metal plating for the arms, legs, and chest to allow for a better fit and more mobility while wearing the armor. This possibly also made it easier to put the suit on and take it off. 
| Mark I • Mark II • Mark III • Mark IV • Mark V • Mark VI • Mark VII|
Mark VIII • Mark IX • Mark X • Mark XI • Mark XII • Mark XIII • Mark XIV • Mark XV • Mark XVI • Mark XVII •
Mark XVIII • Mark XIX • Mark XX • Mark XXI • Mark XXII • Mark XXIII • Mark XXIV • Mark XXV • Mark XXVI •
Mark XXVII • Mark XXVIII • Mark XXIX • Mark XXX • Mark XXXI • Mark XXXII • Mark XXXIII • Mark XXXIV •
Mark XXXV • Mark XXXVI • Mark XXXVII • Mark XXXVIII • Mark XXXIX • Mark XL • Mark XLI
Mark XLII • Mark XLIII • Mark XLIV/Veronica • Mark XLV • Mark XLVI • Mark XLVII
|Mark I • Mark II/Iron Patriot • Mark III|
|Mark I • Mark II|