An insightful thinker, a skilled fighter, and a phenomenally accurate sharpshooter, the Two-Gun Kid became one of the most celebrated of the old western heroes. When the hero team Avengers battled the time-traveling villain, Kang, in the 1870s, Two-Gun was intrigued by the team, struck up a fast friendship with longtime Avengers member Hawkeye and allied himself with the Avengers against Kang, accompanying them back to the 20th century once their battle was won. Two-Gun offered his services to the Avengers and was awarded reserve membership in absentia while he explored 20th century America with Hawkeye as his guide. Two-Gun became increasingly homesick, though, and later returned to his own era.
Years later, Matt's life seemed to have wound down. He married Nancy and had a daughter, but mother and child both died, as did his best friend Boom Boom Brown. These deaths, which might have been prevented with the modern medicine Two-Gun saw in the future, made Matt cynical and fatalistic, an attitude reinforced by historical records of his own death that he had seen in the future. When the dates of his "deaths" as both Matt Hawk and the Two-Gun Kid drew near, he faked his death as Matt Hawk so he could devote his Two-Gun Kid identity to foiling an international conspiracy aimed at controlling the world's economy. The Kid and several allies were seemingly killed in the conclusion of that conflict when the Two-Gun Kid destroyed a massive oil deposit the conspiracy had hoped to exploit. In actuality, the Kid and his allies survived the explosion, and for a time, they rode together as a band of adventurers called The Sunset Riders.
The Sunset Riders soon drifted apart, though, and Matt decided to begin life anew. He resumed his legal career under the alias Clay Harder, taking his new name from a fictional Two-Gun Kid depicted in the dime novels of his day. He was determined to remain retired from the realms of gunfighting and adventuring, but when some of his old gunfighter peers approached him to help protect the town of Wonderment, Montana from corrupt business interests trying to wipe out the community, Matt donned the mask of The Two-Gun Kid once more. Alongside Gunhawk, Caleb Hammer, Reno Jones, Kid Colt, the Outlaw Kid, and the Rawhide Kid, Two-Gun Kid rode into action one last time. Wonderment was saved, but Gunhawk, Kid Colt, The Outlaw Kid, and The Two-Gun Kid were ultimately killed in the conflict.
It was later revealed that She-Hulk, after dealing with the Time Variance Authority, was given the chance to free one time traveler out of continuity limbo. She chose the Two-Gun Kid as he was a former Avenger. It was clarified that his heroic nature prevented him from being returned to his own time, as he would inevitably try to fix things.
In the present time, he learned that his previous modern-day encounters with the Avengers had resulted in his law license and other paraphernalia being kept in an Avengers safety deposit box. Once he learned that She-Hulk worked for a law firm, Goodman, Lieber, Kurtzberg & Holliway, he tried to become her colleague. He soon came to the conclusion, however, that he would never be able to catch up on current laws and became a bounty hunter instead. His first catch was Bushwacker.
For a time he roomed with the Awesome Android, who had reformed and was also an employee for the same law firm. He also used a twin-engine jet cycle to fly around the city. This cycle was donated to him by Hawkeye, an old friend who was aware of his past time-traveling difficulties and the potential for even more.
During the Civil War event, Matt Hawk became a licensed bounty hunter and worked alongside She-Hulk, helping her to apprehend super-villains. For example, he took down the rampaging villain Ruby Thursday with a stun rifle. He was later sent to Arizona to lead the Desert Stars team of the 50-State Initiative. He was injured when his team member the Blacksmith was revealed to be a Skrull and attacked the team. After that, he recovered, and with Komodo, Supermax, and Johnny Cool, aided the Heavy Hitters to protect a dam from an attack by super-powered villain Zzzax.
At some point in the future, Matt Hawk would become too old to continue crime-fighting and returned to the past to a period analogous to the amount of time he had aged. Finding that his old life in Texas and Boston, including his old family and friends, were long gone, and with his knowledge of the future, the aging Matt Hawk relocated to New York in the hopes of surviving long enough to see the dawn of the golden age of heroes.
By 1938, the elderly Hawk was sequestered in a hospital where he was under the care of Dr. Thomas Halloway. Hawk, knowing that Halloway was destined to become the hero known as the Angel, spent his final days telling Halloway of the age of heroes ahead. Halloway believed that Hawk was merely an old man suffering from a creative form of dementia. Soon after, Hawk died of old age, leaving Halloway with a parting gift: His old mask and two revolvers.
Matthew Hawk's soul ended up in Hell because, in his own eyes, despite being a hero he had been a killer. Since the inhabitants of Hell are stuck in the lives they lived, Matt was returned to his appearance from his prime, which allowed him to spend his days killing demons as the Two-Gun Kid.
Following his death in 1938, Hawk's stories of the future inspired Thomas Halloway to become the costumed hero known as the Angel. Halloway wore Hawk's mask and used his two revolvers to honor the hero whose exploits he read about as a child. Halloway was also inspired to write about the early days of World War II and the rise of super-humans during the war. This story, dubbed "The Marvels Project," was passed down along with Hawk's guns and mask to Halloway's grandson Jason, by Captain America, and Hawk's younger self who was still living in the modern era.
Two-Gun Kid was also remembered as the main character of the B-movie The Two-Gun Kid meets Dracula, starring Martin Preston.