In the film, Michael wants to be an only child (like in the book, he is an ordinary child, unlike Matilda). Michael's nickname for Matilda is "Dip Face."
In the book, Michael leaves his little sister alone and at the end, he waves goodbye to Matilda. In the film, Zinnia is the one who waves goodbye and says "ciao" while smiling as he stares dumbly at her.
In both the film and book, he was educated by his father as he is to inherit the used car dealing business in the future; however, in the film, Harry was more into showing Michael some details and he developed an interest and fascination in the business.
In the musical, Michael is lazy and doesn’t even pay attention to Matilda.
When he was in his car seat he uses his toy to play with. When he was older, he threw marshmallows at Matilda, while calling her “Dipface.”
Later in the movie, he says, “Hey, Dipface, have a carrot” and used a spoon to throw the carrot at Matilda, but she turns around and makes it stop in front of her, causing him to look shocked. Matilda then makes the carrot turn around and zoom back over to Michael, who drops the spoon on the counter right before the carrot enters his mouth. Matilda laughs a little as Michael then begins coughing; Harry then calls, “Chew your food! You’re an animal!”
Michael bullies Matilda and his nickname for her is "Dip Face." He wants to be an only child. Matilda also has telekinetic powers and superhuman intelligence, unlike her brother. Michael also throws marshmallows at Matilda.