After nearly a half-century making films, Steven Spielberg’s reputation is that of a populist rather than a subversive film-maker: a man whose body of work drove audiences to theaters more than it did defy artistic convention. There’s something unseemly about that, since Spielberg’s crowning achievement – his ability to give moviegoers what they wanted before they knew they wanted it – was rooted in pushing the proverbial envelope.

Susan Lacy’s authorized HBO documentary is intent on revealing the true Spielberg, the artiste. To do so, she’s assembled an impressively tenured Greek chorus of film-makers, actors, technicians and critics. There are appearances by the director’s film-making peers: Brian de Palma, Francis Ford Coppola, George Lucas and Martin Scorsese. Plus commentary from the stars, producers and collaborators on many of his films (Tom Hanks, John Williams, Janusz Kaminski, Daniel Day-Lewis, Harrison Ford et al). There’s even room for the critics who’ve both praised and pilloried his work, including Janet Maslin and AO Scott. The result is a panegyric that’s at times too saintly but is nonetheless a fascinating exploration of Spielberg’s career.

Lacy sketches the director’s early life as a Jewish wunderkind from Phoenix, Arizona; the son of divorced parents (his mother Leah Adler was a homemaker, his formerly estranged father an engineer), who nearly abandoned his directorial ambitions after seeing Lawrence of Arabia as a teenager. (The film, as Spielberg explains, intimidated as much as it inspired him.)

But by the age of 20 he was directing Joan Crawford in Rod Serling’s Night Gallery; then at 26, Goldie Hawn in The Sugarland Express, which Pauline Kael called “phenomenal” but said showed “no sign of the emergence of a new film artist”. At 30, Spielberg was cavorting with the “movie brats” – Coppola, De Palma, Scorsese and Lucas – who lavish their former fraternity brother with praise and chart his artistic growth, recounting the director’s metamorphosis from boy wonder to box-office moneyspinner to eventual auteur. “The kind of movie he had a sense for was also the kind of movie the audience had a sense for,” Coppola notes.

Lacy, who previously directed PBS’s American Masters series, does the same, in semi-chronological fashion, with most of the Spielberg oeuvre, from Jaws and Raiders of the Lost Ark to Jurassic Park and Schindler’s List, for which the most time is reserved. “Making Schindler’s List made me reconcile with all the vainglorious reasons I hid from my Jewishness,” says Spielberg. “I avoided therapy because movies are my therapy.”

She pays justifiably cursory attention to his less-loved films like Hook, Always, Amistad, The Terminal and Warhorse before pivoting towards the director’s later work, Lincoln and Bridge of Spies, both of which are contextualized as products of his growing interest in democracy and moral rectitude. By omitting some of Spielberg’s lesser work, and its attendant criticisms, the film veers dangerously close to hagiography, but while other documentaries, like The Shark is Still Working and Spielberg: Steven On Set, have concerned themselves with smaller slices of his career, in Spielberg you never doubt that there’s more than enough material to chew on, and justify the film’s considerable length – it comes in at over two and a half hours.

Spielberg also zeroes in on accomplishments which were groundbreaking at the time though elementary today: the moving dinosaurs in Jurassic Park are compared to the advent of the talkies, the lesbian kiss in The Color Purple is rightfully critiqued for its tepidness, and the red coat in Schindler’s List, the movie’s only burst of color, is hailed as a stroke of crimson genius.

The only real tension in the film is relegated to subtext. When Spielberg, in an interview from the 70s, is asked whether his crowd-pleasing films qualify as real art, he somewhat squeamishly notes the pretension in the very question. Lacy glosses over the director’s complicated relationship with his father, too, which took shape in the filial unease of Close Encounters and the tales of torn, suburban families that appear in so much of his work.

That’s not to say Spielberg is all surface-level sycophancy. As a primer for those less familiar with his films – a category as spare as those films are abundant – it functions quite nicely. And as a history of the advancements of late-20th century American cinema, it’s also remarkably precise, even though it takes the work of just a single director as its subject.

But that’s a testament to the man’s outsize influence on film, one that can’t be measured in profit or Oscars. Accordingly, Spielberg shows the extraordinary life of a cinephile turned director, whose work has left an indelible mark, one that’s perhaps so entrenched that we often fail to notice it. As Dustin Hoffman says near the end of Lacy’s documentary, “Steven Spielberg is like a guy who works with Steven Spielberg.” That is to say: curious, learned and zealous, both humble student and consummate master.

• Spielberg airs on Saturday 7 October on HBO in the US at 8pm EST, and on Sky Atlantic in the UK later this autumn.