"Old Man" Marley was Kevin McCallister's kindly neighbor who was rumored to be a serial killer called the South Bend Shovel Slayer.
At some point, Marley had a dispute with his son, distancing him from his family.
He was rumored to be "the South Bend Shovel Slayer," and was said to have murdered his family and half of the people on the block with a snow shovel in 1958. This rumor stated that he kept his victims in a garbage can full of salt, and that the salt was supposed to have turned the dead bodies into mummies. This rumor was told to Kevin by his brother, Buzz after they observed Marley salting the neighborhood sidewalks.
After accidentally being left home alone, Kevin rushed outside, saying that he was "not afraid anymore." However, upon seeing Marley, he turned and ran back inside his house, afraid.
Later, Marley went to a drugstore, where Kevin also happened to be. The boy looked up, saw Marley, and stepped away a little before running off, accidentally shoplifting the toothbrush.
On Christmas Eve, Marley went to a local church to watch his granddaughter perform in a choir. He ran into Kevin there and dismissed the rumors about him, while also explaining to Kevin the difficult situation with his family. Kevin suggested Marley to call his son, and Marley admitted that he was afraid to, thinking his son would refuse to speak with him. Kevin told Marley that he should call his son, and whether or not his son talked to him, he would know and he would not be afraid any longer. Kevin told Marley that he should also do it for his granddaughter, who probably missed him and the presents.
Later, after burglars Harry and Marv captured Kevin at the Murphys' house, and Harry was about to bite Kevin's finger, Marley came in and knocked out both burglars with his snow shovel before taking Kevin back home.
By the next morning, Marley had made peace with his son. As he hugged his granddaughter, Marley saw Kevin through the window of his home. The two waved and Marley went into his home with his family.
- You can say hello when you see me. You don't have to be afraid. There's a lot of things going around about me, but none of it's true.
- (About the church) This is the place to be if you're feeling bad about yourself.
- How you feel about your family is a complicated thing.
- Deep down, you'll always love them. But you can forget that you love them, and you can hurt them and they can hurt you, and that's not just because you're young.
- You're always welcome at church.
- You can be a little old for a lot of things, but you're never too old to be afraid.
- (After hearing about Kevin's experience in the basement) Basements are like that.
- (Smiles) Merry Christmas.
- (While taking Kevin off the hook) Come on. Let's get you home.
- In the novelization for Home Alone, Marley says to Kevin, “You don't have to be so scared of me. All that stuff you hear about me — none of it's true. Just the product of someone's overactive imagination.”