Who is John Grogan from Marley and Me and what is their importance?

John Grogan is a tall, athletic man. He enjoys exploring the outdoors with his young wife, Jenny, and relishes his career as a newspaper columnist. John's fond memories of his childhood dog, Shaun, lead him to agree to Jenny's request for a dog. John is starry-eyed as he remembers how easily Shaun was trained and his excellent behavior. The memories quickly fade as John asks to view the sire and finds himself nearly knocked down by a flurry of yellow fur. John continues to hope that his puppy will not be as rambunctious as this dog.