A widower, he appears as a wise mentor to his daughter, Molly Solverson who is investigating the crimes of Lorne Malvo and Lester Nygaard.
Peggy, not knowing what to do, returns home with Rye stuck through her windshield, where he is later killed by her husband, local butcher Ed Blumquist, in self-defense.
While at the scene, he notices Kansas City mob associates Mike Milligan and brothers Gale and Wayne Kitchen observing him intently, and calls ahead so Hank can detain them and intimidate them into leaving the state.
Later that night, Lou sees a light on inside the closed butcher shop and finds Ed working late, as he is disposing of Rye's body in a meat grinder.
Lou eventually leaves unaware of what was really happening, and Ed finishes grinding Rye's body as strange flashing lights illuminate the exterior of the butcher shop.
They encounter a local typewriter salesman named Skip Sprang, who had enlisted Rye to talk Judge Mundt into un-freezing an account, acting suspiciously outside of her office.
After escorting presidential nominee Ronald Reagan's campaign bus to the state line, Lou links the Blumquists to Rye's death after Ed and Peggy stage a wreck to cover up the damage and take the car to local mechanic Sonny Greer, and Sonny catches Gerhardt enforcer Hanzee Dent inspecting the car.
She accepts a deal that will give her family amnesty for previous crimes they have committed in exchange for information about how the Kansas City syndicate runs their drug operation.
When Lou strongly opposes this idea knowing that Milligan would see right through the ruse, Cheney has him escorted to the state line, though Hank elects to stay behind.
After Ed and Peggy agree to the plan in exchange for lesser criminal charges, the police set up an ambush at the motel meeting spot, only for Hanzee to observe their actions from a distance.
Lou arrives at the motel too late as the Gerhardts have ambushed Cheney and the other officers and massacred all of them, only realizing their mistake when Hank and Ben begin shooting back while in uniform.
He fires at Bear, who is unfazed, and begins to wrestle with and strangle Lou before the same UFO that Rye encountered appears above them, distracting nearly everyone left alive.
Lou uses the opportunity to shoot a distracted Bear in the head, while Peggy uses a pot of boiling coffee to wound Hanzee in order to escape with Ed.
With the entire Gerhardt family and all of the South Dakota state troopers now dead except for a wounded Hank and Schmidt, Lou continues his pursuit of both the Blumquists and Hanzee.
"[4] Alan Sepinwall of Hitfix, wrote that "there's still that irrepressible sense of upper Midwestern politeness, even in the face of horror and madness, and given spectacular voice by Wilson.
He doesn't much resemble the young Keith Carradine, but the role's otherwise a perfect fit for the contrast between his bland, square-jawed demeanor and the obvious intelligence that's always flashing underneath.
Watching Lou slowly but surely untangle the mess he's been handed gives you a fine idea of where Molly got her investigative gifts.