A family learns important life lessons from their adorable, but naughty and neurotic dog. John and Jenny Grogan escape the brutal Michigan winters and relocate to Florida to work as reporters. They adopt Marley, an incorrigible yellow labrador retriever, and their misadventures with him become the topic of John's newspaper column. As Marley wreaks havoc on their household, Jenny becomes pregnant, loses the baby, and later gives birth to two healthy boys. Despite experiencing postpartum depression, Jenny realizes Marley is an indispensable part of their family. When Marley's health deteriorates, he is euthanized and buried in their front yard.

Marley, an adorable and mischievous puppy, wreaks havoc on his new family with his playful antics and unending energy. As they navigate the ups and downs of puppy parenthood, Marley brings chaos, laughter, and unexpected life lessons to the family.