Summary Being the elder patriarch of the Pickles family, and young at heart, he likes to be adventurous. Occasionally, he flirts with women. He is commonly thought of as having a wild imagination from the many exaggerated stories he tells of his earlier years. In these stories, the number 15 is prevalent in various ways. Whenever Lou appears, his usual routine is to fall asleep in the middle of babysitting the kids and telling them a story, etc. He loves his grandchildren deeply, and always enjoys spending time with Tommy and the others.
He shares a rivalry with his cousin, Miriam, but besides his rivalry with Miriam, he's had several other rivals. His bowling rival was Billy "Strike" Maxwell (seen in "King Ten Pin"), however, Lou later regains his honor by beating him after it's revealed that Maxwell was cheating the entire time. He also has a recurring rival with Conan McNulty, with Conan often lying to him and cheating.
When his wife Trixie has to go out of town, Lou takes care of his sons, and while he loves them, he has a great frustration with their constant bickering. Over the years, Lou has had many jobs, including a soldier in the war, a cook, a repairman for small appliances, and a detective. Lou is also a bit of a schemer such as when he pretended to be ill to shirk out of doing gardening so he can catch up with the sleep he lost while being out all night in "Grandpa's Bad Bug". He has quite a talent for playing the trumpet, as he was given a solo for the war veterans concert in "Grandpa's Teeth". One of the things he loves to do is fishing and mostly watching TV, he's almost always seen watching a show involving fishing. While Lou enjoys doing new things, he can be very stubborn with trying some new things. He frequently compares the modern day world to the way it was in his day, often bragging on that the way something is done is nothing compared to how he did it when he was younger. He is, however, often thought to be making these stories up.
Looks Lou Pickles has peach skin and a pair of white eyes with black pupils. He has gray hair and is often shown wearing a purple shirt and a green vest, green pants, and brown shoes. He looked just like his son, Drew Pickles, when he was younger, but as he got older, he now looks more like his other son, Stuart Pickles. In All Grown Up!, he wears a green jacket over a blue vest and white shirt, a blue bow tie, light yellow pants, and brown shoes. In Seasons 2-5, The color of his jacket is changed to red.
In the 2021 series, Lou wears brown glasses, a purple tie-dye shirt long-sleeved shirt, tan pants, purple socks, and brown sandals. He also has a green fanny pack around his waist and his remaining hair braided on the back of his Head.