He was portrayed by Martin Freeman in his first villainous role.
He was an insurance salesman from Bemidji, Minnesota. His life is changed when a mysterious contract killer named Lorne Malvo comes to town.
Lester was born in 1966. During a mouse dissection in Mrs. Knudsen's class, Lester fainted. He also fainted when a girl had her period in gym class. In one such instance, he was shoved into a barrel and rolled onto a highway. In his senior year, he went to the prom with Pearl, his future wife. The two married around 1988, when Lester was in his early twenties.
Lester broke his own nose to which Lorne replied that he would kill a man over such treatment. Lester asked Lorne to kill Sam. Lester and Pearl visited Chaz to celebrate their nephew Gordo's birthday. Lester tried to apologize, but was instead ridiculed for being a weak older brother. Lester hit Chaz and drove home with Pearl. Lester confronted Lorne about the killing, but was Pearl taunted Lester, he finally snapped and killed her with a hammer. He called Lorne and asked for help cleaning up the murder, but planned to frame Lorne when he arrived.
Lester followed Lorne into the basement after Deputy Molly Solverson arrived. Down there, Lester found Lorne is no longer there. Lester, thought quickly and ran his head into the wall to knock himself out and made it look like he and Pearl were victims of a home invasion. He woke up in the hospital the next morning and noticed he had a peculiar hand wound. (The Crocodile's Dilemma)
Lester is seen attending a service for Pearl. Chazz offers him a spare room to stay in for a few days, which he agrees to. He returns to his house and starts having flashbacks
of the night Pearl and Vern died. He then gets a visit from Molly and Bill, who ask him a few questions about what happened. He gives them a very half-hearted story which Bill is satisfied with, and they leave. He packs a few days worth of things and moves into Gordo's bedroom, while Gordo sleeps on the couch in the living room. He finds a jar of urine in Gordo's cloest. Later at dinner, Lester tells Chazz he plans to sell the house like he recommended, much to Chazz's surprise. He also decides to join him on the hunting trip this weekend.
Later that night, Lester goes to the pharmacy to pick up antibiotics to treat his hand wound. He is approached by Molly, who continues to question him as he tries to leave without picking up his medication. He is followed out to the parking lot, and Lester tells Molly to stop harassing him as he drives away.
Lester visited Sam Hess's widow Gina Hess to discuss the payout of life insurance. Gina flirted with Lester, but they stopped when her son Mickey accidentally shot his brother Moe with a crossbow.
Fargo hitmen Numbers and Wrench, who were watching Lester at the Hess residence, visited him at his work. They tried to intimidate him and get information, but left when Deputy Molly Solverson arrived. She pretended to be interested in an insurance plan, but in reality only came to subtlely show Lester a picture of Lorne Malvo. She left after seeing his startled reaction.
Lester was later kidnapped by Numbers and Wrench and taken to a frozen lake to be killed. However, he was able to escape after attacking Numbers with a taser. He attacked police offer Knudsen in order to be taken away. Unfortunately for him, Numbers and Wrench were soon arrested as well and all three ended up in the same police cell. Numbers and Wrench torture Lester and extract the name of Sam Hess's killer: Lorne Malvo. He planted evidence in Chazz's gun safe, such as the hammer used to kill Pearl, and also put a handgun in Gordo's schoolbag.
After Lester told the police that Chazz was the real killer of Pearl and Vern, he didn't say this before because he was Lester's brother. Lester was released from custody, and returned to the Hess residence where he had sex with Gina, promising to work hard to get the life insurance payout but knowing that it was actually canceled for nonpayment. Lester married his coworker Linda Park and moved into a new house. He left Bo Munk Insurance to create his own business, Nygaard Insurance.
Whilst attending an insurance awards ceremony, Lester spotted Lorne Malvo. He refused to walk away from Malvo, causing Malvo to kill his three companions. However Lester grew scared and assaulted Malvo before running to his hotel room. He and Linda hurriedly left and they flew home to Bemidji, with plans to escape immediately to Acapulco, Mexico. Molly Solverson visited Lester's house to ask him questions about the Las Vegas murders, but he did not give any information.
Lester and Linda quickly made arrangements for their trip to Acapulco, Mexico. They visited Lester's new shop to collect money and passport. Lester feared that Malvo could be inside, and so sent Linda in wearing his orange hooded coat. Lester was shocked when Malvo was inside and shot Linda in the head. Lester immediately went to Lou's Coffee Shop and ordered food and drink for two people, insisting Linda was picking up some items from his shop. He used a pay-phone and disguised his voice to report gunshots.
Lester was later questioned by police about the death. He was released, although was accompanied home by FBI agents Budge and Pepper. After Malvo killed Budge and Pepper, Lester and Malvo had a stand-off in the house, in which Malvo's leg got caught in a bear trap set by Lester, Lester tried to shoot Malvo but he threw his Salesman of the Year trophy at Lester, breaking his nose again, Malvo managed to escape to the forest, Lester went on the run. Two weeks later, he was in Glacier National Park, Montana. He was pursued by police on snowmobiles before he went out alone on a thin layer of ice on a frozen lake. He died after the ice cracked and he fell into the water.
- Lester bears similarities to Jerry Lundegaard, a character from the film of the same name, as they are incompetent salesmen who constantly lie and seek criminal assistance, however Lester reveals to be far more vicious than Jerry, even smiling after framing his brother for the murder of Pearl.