Walt is first seen in "Boys' Night", when neither Phil nor Claire are willing to go to his house to retrieve their baseball, despite the fact that it was their only one. The two seem scared and intimidated by Walt, and Claire claims that if "Freddy Krueger and Hannibal Lecter had a love child, he would be scared of Walt Kleezak". Phil states that while he does not have a bad word to say about anyone, he states "Mr Kleezak is not a nice person". Later in the episode, Walt comes over to the Dunphy's house with onions, as a gift, and states that he will not harm Luke. The family and Walt later become friends, largely through Luke and Walt's relationship.
Later in "The Last Walt", it was revealed that Walt had suffered a heart attack and later died.
Luke Dunphy was friends with Walt. He and Luke had a mutual love of playing video games.
In "Boys' Night", Walt makes his first appearance, Claire and Phil tell Luke not to play with him as they seem to find him creepy and think he isn't a nice person. When the Dunphy family are playing sports in their backyard, Claire bats the ball into Walts' backyard and they finish the game as Phil and Claire are afraid of going to his house to ask for it back nonetheless Luke ignores his parents and curiousity gets the better of him, as he goes around Walt's house and is the only member of his family to risk getting the ball back, Luke asks questions to Walt, at first Walt isn't very keen on Luke and doesn't trust him. Luke annoys Walt so much that he gives up and tels Luke to get his ball. Later on we see Luke come back home and tell his parents that he hung out with Mr. Kleezak in his house and Claire seems disappointed thinking that he is a creepy old man, but Luke tells them differently, as he has actually seen his personality and not judged it. Claire tells Luke that he can't go back to Walt's house because he's weird. Luke then tells his parents that it's unfair and they don't know him as they're too afraid to talk to him. Claire and Phil then go over to tell him they are concerned about his friendship with their son, Walt gets offended that they think he is a pervert and he makes them leave his house. In the end, Walt stops by the Dunphy house and gives them Onions from his garden, he then tells them he used to be a fireman and he doesn't hurt kids. Feeling bad Claire and Phil invite him in but he doesn't come in. Seeing that Luke may be right and he is a kind, friendly old man and they judged him too quickly they accept him being a family friend.
In "Lifetime Supply", Luke asks Claire if he can invite Walt over, Claire asks Luke if he thinks it's weird to have an 85 year old best friend, Luke thinks it's cool that he's older than him and has been in the war. We later see Luke and Walt playing games on the Dunphys' couch, Phil is there with them, but it's only because of the news he thought he was going to receive and not because of supervising. When Luke takes a break for the toilet, Phil bonds with Walt over new he thinks is true: he is going to die, although Walt reassures him that the doctors told him he'd been dead 10 years ago and he is still alive.
In "Election Day", Phil gives Walt a ride to pick up his glasses. When Walt's tank starts to run out, Phil panics when he says that he doesn't have any more tanks at home and forgot to order them, and when he says that he needs to take his pill, which he does have, he says he needs it with food. So Phil drops him off at the polling station where they need to vote for Claire, Walt gets food to take with his pill first so that he'll be okay. Walt says that he doesn't like to vote for the government as they seem to screw him over, but since he had such a nice day with Phil, who says he thinks is a nice kid, he decides to vote for Claire, which goes against everything he believes in.
In "The Last Walt", in the opening scene, Phil and Claire have an "interview" where they give the news that Walt has died. Phil and Claire break the news to Luke, however Luke says that he is OK, and just wants to get back to his video game. Later on Phil and Claire see Luke go int Walters' house, and think it's to say goodbye to (his house and spirit). Phil and Claire then see Luke come out and take Walt's TV with him. A while later Luke brings Claire to Walt's house and Claire begins to get worried when Luke doesn't want to say a few words about how he felt about Walt and thinks that he isn't dealing with it in a healthy way. In the same scene Claire realises that she can't tell people someone has died without smiling, which is a coping mechanism for her, and Luke opens up about how he feels about Walt dying, Claire then comforts him although Luke still doesn't cry.
- He needed oxygen tanks to breath.
- He had fought in the war.
- He liked playing video games, like Luke.
- In "Boys' Night", he revealed he was once a fireman.