Luke Skywalker was 19 years old in "Star Wars: Episode IV – A New Hope." This age is established based on the official Star Wars timeline, as Luke was born at the end of "Episode III: Revenge of the Sith," which is set 19 years before "A New Hope" takes place

. Although his exact age is never explicitly mentioned in the film itself, the broader Star Wars lore and tie-in media confirm he is 19 during the events of "A New Hope"