#7: Johnny Galecki as Rusty Griswold
Rusty Griswold is the laid-back, slightly awkward kid trying to survive his dad’s ambitious holiday plans. His dry humor, patient reactions, and sibling squabbles help shape the film’s family dynamic. Rusty’s calm presence contrasts perfectly with Clark’s intensity, making his understated jokes some of the movie’s most memorable moments.
During this period, Johnny Galecki was a young actor just starting to gain television and film experience. He had appeared in a few small roles, steadily building his résumé. Christmas Vacation became one of his earliest notable performances, giving him national exposure long before he became a household name.