Starring Zac Efron, Christian McKay, and Claire Danes. Rated PG. Opens Friday, December 11, at the Cinemark Tinseltown

The seeds of an icon’s greatness, and of his demise, are on display in Me and Orson Welles, a superb entertainment that carries much cultural history just beneath its lighthearted surface. Above all, the movie sports a career-making performance from Christian McKay, who effortlessly embodies the 22-year-old Welles on the eve of his own major breakthrough.

The Me of the title is fictional Richard Samuels, a high-school drama student—played well by 17-again Zac Efron—who drifts into the Great Man’s orbit when the latter is about to launch his modern-dress version of Julius Caesar. This being 1937, modern means fascist, and Welles’s Mercury Theatre is part of a leftward upswing in American arts, although this isn’t highlighted here and may not have been that important to key players like impish Joseph Cotten (James Tupper), surly George Coulouris (Ben Chaplin), and Norman Lloyd (Leo Bill, the cast’s weakest link).

Also aboard are sad-faced Eddie Marsan as producer John Houseman and glammed-up Claire Danes as an ambitious administrator to whom young Richard is drawn after he’s literally plucked off the street to play a musical page to Welles’s brooding Brutus. The boy learns plenty of lessons, some not so nice, from his new hero.

Using a screenplay that Holly Gent Palmo and Vincent Palmo Jr. crafted from Robert Kaplow’s novel, director Richard Linklater rather unexpectedly shot the whole thing on soundstages in England. The theatrical re-creations are brilliant, and even more delightful is a long sequence of the inner workings of live radio and Welles’s nimble, self-serving mind. A subplot with Zoe Kazan as a young writer who also engages Efron’s callow character may be less substantial. But everything here works to build an indelible portrait of a man, and another time and place.