Growing up in Texas, Chris Kyle's (Bradley Cooper) father, Wayne (Ben Reed), instilled in him the vital skills of hunting and marksmanship. Wayne emphasized the importance of never letting one's rifle touch the ground and insisted on standing up for those who cannot defend themselves against bullies.
As years pass, Chris finds himself as a rodeo cowboy, but his life takes an unexpected turn when he returns home early to discover his girlfriend in bed with another man. While contemplating this shocking moment with his brother Jeff (Keir O'Donnell), Chris becomes inspired by news coverage of the tragic 1998 U.S. embassy bombings, which prompts him to enlist in the U.S. Navy. At the age of 30, he successfully completes SEAL (Sea, Air, and Land) training, fueled by a profound sense of patriotism, convinced it is his duty to protect the nation he holds dear.
In his life journey, Chris encounters Taya Studebaker (Sienna Miller) at a bar, although she initially finds him unappealing due to her misconceptions about military personnel, especially SEALs. Nevertheless, Chris's genuine charm and politeness gradually break down her walls, leading to a budding romance as he persists in his sniper training.
Their love story culminates in marriage before Chris is deployed to Iraq following the September 11 attacks in 2001, assuring Taya that his tour will be brief, lasting only six weeks. Chris's harrowing experiences begin with the distressing task of taking out a woman and a boy who pose a threat to U.S. Marines on patrol. His sharp instincts and keen attention allow him to identify and neutralize threats, earning him the nickname "Legend" for his prowess as a sniper, despite the toll it takes on his psyche.
During his time in Iraq, Chris faces formidable challenges, including a skilled Iraqi sniper known as "Mustafa" (a Syrian marksman with Olympic experience), who is targeting American forces with deadly precision. Amidst the chaos, Taya awaits the arrival of their first child, her worries escalating due to the perilous statistics surrounding U.S. military personnel in Iraq. Chris also learns that his brother Jeff has been deployed, intensifying his internal struggles.
Tasked with hunting down notorious insurgent leader Abu Musab Al-Zarqawi, Chris experiences the horrors of combat firsthand, witnessing the mistakes of inexperienced Marines. When a plan to locate an insurgent leader backfires, the consequences become devastatingly real, including the deaths of key figures involved in the operation, while simultaneously, a bounty is placed on Chris's head.
Returning home, Chris grapples with his traumatic memories, leading to heated arguments with Taya over the horrors he witnessed, leaving her feeling alienated from him. As the war beckons him back, now promoted to chief petty officer, Chris finds himself increasingly distant from his family, even during the birth of their daughter.
On his final tours, Chris faces escalating violence, where skilled snipers and heart-wrenching losses compound his feelings of guilt and obligation. He finds himself haunted by the men he couldn’t save, ultimately seeking solace through helping fellow veterans once back home. His path catches up to him on February 2, 2013, when Chris, in a hopeful spirit and eager to support a fellow veteran, heads out, unaware that it will be his last interaction—struck down by a man he sought to assist.
The somber conclusion reveals the profound impact he left behind as the nation mourned, with thousands lining the streets to pay their respects, encapsulated in a moving memorial service at Cowboys Stadium.
