After Shannon had been illustrating books for a while, he was encouraged to write his own book. For his first book, Shannon decided to write a book about baseball, because it was a topic that he already knew well. This book was entitled, ''How Georgie Radbourn Saved Baseball'' (1994), where Shannon was able to incorporate his dark painting style, which came from his love of villains, with a story about baseball. This book got Shannon interested in writing, and he has continued writing books ever since, and has decided to focus primarily on children's books.
Shannon's arguably most famous masterpiece came with the book entitled ''No, David!'' (1998). After Shannon had been writing children's books for several years, his mother found a book that he made when he was five years old and sent it to him. This book consisted entirely of the words "no" and "David" because Shannon said that these "were the only words I knew how to spell at that time." Because of this, Shannon decided to make an actual book out of this where he retold the story of a mischievous child named David, naturally, based on himself, whose mother is always telling him 'no' because he is constantly jumping on the bed, banging pots and pans, and playing baseball where he is not supposed to. But she reassures him at the end when she finally says, "Yes, David, I love you." In addition, Shannon wanted to keep this book realistic, so he decided to keep the illustrations as close to the original ones as possible. As a result, Shannon said, "So that's how I found out what, deep down, I knew all along. I love storytelling. And I'm really lucky that I get to do it for a living." According to a review of this book, "Readers won't be able to resist taking a walk on the wild side with this little rascal, and may only secretly acknowledge how much of him they recognize in themselves." ''No, David!'' (1998) was named a Caldecott Honor Book in 1999.
Shannon followed ''No, David! '' (1998) up with ''David Goes to School'' (1999) and ''David Gets in Trouble'' (2002). In ''David Goes to School'' (1999), Shannon introduces David to the reader in a school setting. The book goes through all of the normal things that occur at school, continuing with the same "no" phrase, but instead of David's mother saying "no" all of the time, it is the teacher who is saying "no". In Shannon's latest book in the series, ''David Gets in Trouble'' (2002), David is back and up to his old tricks, but this time he has expanded his vocabulary and tries to give his mother every excuse you can think of for all of his bad actions. For instance, David gives such excuses as "I forgot," "it was an accident," and "it wasn't me". In addition to the previous books, this book was also reviewed and recommended by Adele Greenlee, who said that, "Children who enjoyed ''No, David!'' (1998) and ''David Goes to School'' (1999) will welcome this lighthearted sequel."
Another popular book by David Shannon is ''The Rain Came Down'' (2000), when a summer shower that is unexpected causes great chaos in a small neighborhood. This huge shower causes a line of temper tantrums, but when the clouds suddenly break, all of the sour moods go away. In a review on this book, the author says, "Shannon expertly uses vertiginous angles as he builds suspense, then calms things down with a set of subdued portraits and a view of a quiet afternoon picnic."