Biff
Biff is deceitful about his life but his dishonesty is compounded, as Willy is dishonest about him. When Biff stole a football from the locker room when he was in high school, and he claimed that he took it because the coach told him to work on his passing. Willy acts for a moment as if Biff should return it, but when Hap implies that Biff was wrong for taking the ball, Willy defends Biff and declares that the coach, rather than being angry with Biff for stealing, would have been proud and impressed with Biff's initiative. Willy tells Biff that it's OK that he took the ball because the coach likes him. Willy tells his son it's perfectly fine to steal from people, as long as you are well liked; they'll let you get away with it. Willy finds it impossible to understand how someone who was as popular and well liked as Biff was in high school, could have grown up to be such a failure. Willy always believed that Biff's popularity would naturally lead to great success in the business world. But that's not the way things have worked out for Biff, and Willy is baffled by it. Willy shows this by telling Biff to pretend his work out West was business related instead of farm work to impress Oliver. Willy also lies to Bernard about how Bill Oliver called Biff in to work for him. He is intimidated by Bernard's success and embarrassed by how little Biff has done with his own life. Willy lies to make Biff seem important and successful in the same way he does with himself. Biff’s dishonesty is highlighted when he stopped working for Bill Oliver because he was accused of stealing a carton of basketballs, but despite that, Biff believes that Oliver will loan him $10,000 to start a ranch. Biff, like Willy, is creating a dishonest vision of the past. He stole from and lied to Oliver when he worked for him, and now he's lying to himself by asserting how much Oliver liked him. His lies are convinced enough to become the truth, and he can't remember which version of the story is right.
Willy’s dishonesty about career
Willy has outlived his contacts and his popularity, if he ever had it, and is now unable to make any money. He believes that a man's role is to earn money to support his family, and on those terms Willy is a total failure. This leads to him lying repeatedly about his career to his family. The dishonesty begins with Willy telling Linda that he came home because he couldn't drive anymore. The reason, he later admits, is that he almost ran over a child in Yonkers, and it spooked him. But he doesn't lie only about the reason for his return, he also lies about his importance to the company in New England, and how he'd already be running New York if his original employer were still alive. There's no guarantee that Willy and his former boss were good friends, and Willy hasn't been important in New England for a long time, if indeed, he ever really was. He creates a false image of a skilled salesman in demand, when in reality he is unwanted. Willy lies to the boys about meeting the mayor of Providence. He likes to make his sons believe that he's an important and great man, when in reality, he is just an average guy, like everyone else. Willy gets trapped in the false image he has created, believing the lies he has been telling himself for years. He is unable to confront reality and has the expectation that people are going to react to him as a successful and important salesman. When he realizes that he's a failure, and everyone knows his "success" is a fake, life is no longer worth living. Willy feels worth more dead, than alive. A further example of Willy’s dishonesty in relation top his career is when Linda asked him how well he did on his trip, Willy lied about how much he sold. He admitted the truth only a few sentences later. Willy contradicts himself continuously.
one minute the Chevy is the greatest car ever built, the next minute it's a hunk of scrap metal. As Willy is talking to Linda about Biff, he says that he's lazy and that's why he's a failure. But in the next breath, Willy says that he doesn't understand why someone as hard-working as Biff isn't more successful. Willy's speech is constantly riddled with inconsistencies and contradictions. These contradictions make his convictions completely unreliable.
Linda
Linda’s morality and honesty are used as a foil to highlight the other characters dishonesty. When Willy sent the boys to steal sand from a construction site so they could rebuild their house he is convinced that stealing the supplies is not wrong. This dishonesty is made dramatic as Willy is even proud of the boys being so fearless. Even when the watchman is chasing Biff, Willy still refuses to admit that they're wrong. Linda, however, seems to know that what they're doing is dishonest, and she worries about the boys getting into trouble for it.
Biff’s realization of dishonesty
Miller uses Biff’s realization of his dishonesty to create dramatic effect, he does this by contrasting Happy and Biff. Hap lies to the girl he's hitting on so that he can get her attention. He is a natural at dishonesty, and he does not feel bad about it at all. Biff, however, realized in his meeting with Oliver, that he'd never been a salesman, just a shipping clerk. He realizes at that moment, his entire life has been a lie. His father and his brother are liars, too, because they all pretend to be what they aren't. Biff finally confronts Willy about the lies they've all been living. He tells Willy that stealing has cost him every good job he's had since he was in high school, and that they all have been lying to each other about who and what they really are. Miller uses Biff’s vivid realization of his dishonesty to create excitement.