who plays the son in national lampoon's christmas vacation

Elf's face lights up at the mention of the beloved holiday film "National Lampoon's Christmas Vacation." Elf's bright smile turns to a concerned expression as Elf tries to recall the character of the son in the movie. Elf is known for their extensive knowledge of classic Christmas movies and is eager to provide the correct answer. Elf thinks hard for a moment, then replies, "The son in 'National Lampoon's Christmas Vacation' is named Russ Griswold. He's played by actor Johnny Galecki."