Clinton Francis "Clint" Barton, also known as Hawkeye, is an extremely skilled marksman, a former special agent of S.H.I.E.L.D. and one of the founding members of the Avengers.
Known for his use of the bow and arrow as his primary weapon, Barton had become one of the best agents of S.H.I.E.L.D., responsible for the recruitment of Black Widow, whom he developed a strong friendship with.
Assigned by Nick Fury into watching over the Tesseract, he was brainwashed by Loki and used as his pawn for all his evil schemes. However, following their Attack on the Helicarrier, he was freed from Loki's mental controls by Black Widow and joined the Avengers to fight against Loki's Chitauri army in the Battle of New York, ending Loki's Invasion, before Hawkeye had returned to his work as a S.H.I.E.L.D. agent.
Hawkeye continued to work with S.H.I.E.L.D. until its collapse following the HYDRA Uprising, he and the Avengers worked to bring down the remnants of HYDRA, eventually capturing Wolfgang von Strucker and ending the organization's threat to the world.
However, Hawkeye was pulled back into their fight as Tony Stark had inadvertently used HYDRA as well as some Chitauri technology to create Ultron. As Ultron tried to destroy their world, he allied himself with Pietro and Wanda Maximoff and Barton focused much of his efforts in convincing them to change sides while keeping all the Avengers safe by bringing them into his family home.
During the final Battle of Sokovia, Hawkeye's life was saved by Quicksilver's sacrifice, resulting in Barton retiring from the Avengers to return to his family.
Despite living happily within retirement for a brief time, Barton was recruited by Captain America to help him during his fight against these newly produced Sokovia Accords, which forced Rogers to protect his friend Bucky Barnes from being arrested for a crime he did not commit.
Feeling that he owed a debt to Rogers and Maximoff, Hawkeye had joined in the Clash of the Avengers, fighting against Iron Man who was in support of the Accords. Despite putting up a good fight, Hawkeye and most of their team were eventually defeated and imprisoned at the Raft under the order from Thaddeus Ross, only to be freed by Rogers. Barton returned back to retirement and, after striking his deal with Ross, was then placed under his house arrest.
In the wake of the Snap, Barton then went onto a grief-fuelled rampage against criminals for five years as a vigilante named Rōnin. Having been found by Black Widow, Barton was then convinced to return to the Avengers to attempt to reverse the Snap.
Hawkeye joined the team in enacting the Time Heist in order to obtain the Infinity Stones, during which he witnessed Romanoff sacrifice her life so Hawkeye could reclaim the Soul Stone. However, as the Avengers had succeeded in their goal, they were ambushed by Thanos, with Hawkeye being ordered to ensure Thanos could not get the Nano Gauntlet.
Eventually, Thanos and his entire army were defeated, as Tony Stark had sacrificed his life, allowing Barton to then return home with his beloved family, while he still mourned Romanoff's death.