In 1992, Larry Cancro, the chief of marketing for the Red Sox, had the idea to create a mascot to make Fenway Park more appealing to children. The mascot was designed to be a green monster, and given the backstory that he had been living in the
Green Monster for years, and had finally come out. Writer Rick Dunfey was hired to write
The Legend of Wally the Green Monster, a children's book about the mascot, and decided to name him Wally in reference to the wall. The book was published under the pen name Maxwell M. Carey. On April 13, 1997, Wally the Green Monster was revealed to the public on "Kids Opening Day" in Fenway Park, and copies of Dunfey's book were distributed for free.
Jerry Remy, a Red Sox player and later commentator, co-wrote a series of books about Wally. Throughout his history, Wally went through a number of redesigns, including a more muscular form in 2004 and having a beard in 2013, due to many other Red Sox players having beards. In 2016, the Red Sox introduced Tessie, another mascot designed to be the younger sister of Wally, named after the song
"Tessie" sung by the
Royal Rooters. In July 2012, the mascot costume was reported as missing, leading the Boston Police to put out a bulletin looking for Wally. The incident was later revealed to be a misunderstanding; a Red Sox employee had taken the costume for scheduled appearances and had decided to wear it around Boston. The employee was not charged. On April 2, 2017, the Red Sox premiered ''Wally's Opening Day'', a 30-minute animated special about Wally preparing Fenway Park, for the 20th anniversary of Wally's release as part of an initiative by the club to appeal to children. ''Wally's Opening Day'' was the first television animation produced by a Major League Baseball club.
Linda Henry, wife of Red Sox principal owner
John W. Henry, served as executive producer. ==Rivalry==