Mrs. Levenstein is the wife of Noah Levenstein, mother of Jim, mother-in-law of Michelle, and grandmother of Evan.
She appears in all 4 of the primary films (though her appearance in American Reunion was only a brief cameo).
Mrs. Levenstein is aware that her husband embarasses Jim with his long speeches, and in American Pie 2, she advises him to just "be cool".
Her role in the films, is relatively small. She only had 2 scenes in the second film, with little dialogue. Her most notable line in the film is: (upon seeing Jim in bed with a girl) "I got your favorite--Oh My God, They're fucking!!". She's never seen again for the rest of the film.
She plays a somewhat larger supporting role in American Wedding, having more scenes and dialogue than she did in any of the other films.
In The Naked Mile, Noah mentions that she is interested in trying Kamasutra to help improve their apparently boring sex life.
She is not mentioned in Beta House but briefly mentioned in The Book of Love with Noah saying they've been married for over 30 years because he loves and respects her.
Unfortunately, between the events of The Book of Love and American Reunion, Mrs. Levenstein passed away from an unspecified illness or accident. Her death left Noah a depressed and lonely widower. He later found new love in Jeanine Stifler, the mother of Steven and Matt.
Despite her death, she is seen briefly in a home video of Jim's Bar Mitzvah. Upon seeing her on the screen, Noah and Jim feel sad.