Chewing the Scenery is an expression used in relation to acting, especially, when the actor is being overly dramatic and exaggerates emotions too much.
Its first documented use is tied to Mary Hallock Foote’s acting in Coeur D’Alene in 1894, listed in the Random House Historical Dictionary of American Slang.
The expression has been adopted by theater-goers around the world since that time.
“Chewing the Scenery” is a phrase that is still largely in use, and since the development and popularity of motion pictures, it is also used in relation to movies.
It was first defined on Urban Dictionary in 2009, followed by another entry in 2011.