Roberts Blossom as Old Man Marley
The mysterious man who lived across the street from the McCallister home usually scared Kevin with his occasional waves. This is apparent at the beginning of the movie. However, still alone, Kevin makes his way to the church for Christmas Eve. Here he finds his neighbour, Marley sitting in the pews.
This is where one of the more heartfelt points of the movie takes place, over a conversation between the two. Later in the movie, it is Marley who helps Kevin stay safe and protect his home, by knocking the two robbers with a shovel!