Every genre has ancestors, and The X-Files was unusually open about its own. Its informants meet in parking garages. Its agents work inside an institution that may be hiding the truth from them. Its villains are rarely monsters and more often men in suits who have decided what the public is allowed to know. That's not the language of science fiction. It's the language of the American conspiracy thriller of the 1970s.
Pakula's trilogy
Alan J. Pakula's films Klute (1971), The Parallax View (1974) and All the President's Men (1976) are often grouped as a "paranoia trilogy." Together they defined how a generation of filmmakers pictured institutional power: vast, impersonal, and mostly invisible.
The Parallax View in particular feels like a blueprint for the X-Files' worldview. Its hero, a reporter played by Warren Beatty, investigates a political assassination and discovers a corporation that recruits killers. The film is shot to make him small. He's dwarfed by architecture, framed against empty spaces, and finally swallowed by the system he's investigating.
Gordon Willis and the dark
Both The Parallax View and All the President's Men were photographed by Gordon Willis, the cinematographer whose fondness for deep shadow earned him the nickname "the Prince of Darkness." Willis was willing to leave actors' faces in near-total darkness when the scene called for it, which was a radical choice for studio films at the time.
You can see a direct line from Willis's work to the X-Files. The parking-garage scenes in All the President's Men, where Robert Redford's Bob Woodward meets the informant known as Deep Throat in near-darkness, became one of the most imitated set-ups in American film. The show didn't just borrow the staging. It borrowed the name. The X-Files' own Deep Throat, Mulder's first informant, takes his name from the Watergate source. Chris Carter has also pointed to Donald Sutherland's Mr. X in Oliver Stone's JFK (1991) as an influence, and the show later gave Mulder an informant called X.
Three Days of the Condor
Sydney Pollack's Three Days of the Condor (1975) adds another piece. Robert Redford plays a CIA researcher who comes back from lunch to find his colleagues murdered, and spends the film unsure who in his own agency he can trust. The idea that the enemy might be inside the institution, and that the hero can't simply call for help, runs through the X-Files from beginning to end.
Television's own ancestor
The show also had a television ancestor. Kolchak: The Night Stalker, which ran in 1974 and 1975, followed a reporter who kept stumbling on monsters that the authorities refused to believe in. Carter has named it as an inspiration, and its structure, a weekly creature investigated by someone nobody takes seriously, is recognizably the X-Files' monster-of-the-week format.
The 1990s update
What The X-Files did was combine those threads and update them for its own decade. The 1970s thrillers were shaped by Vietnam and Watergate, by a public that had learned its government could lie. The X-Files arrived in the 1990s, after the Cold War, when that distrust had become a kind of background condition. The show's paranoia is less angry than its ancestors'. It's weary, and sometimes funny.
It also added a woman at the center. Carter has said Dana Scully was partly modeled on Clarice Starling from The Silence of the Lambs (1991), down to her red hair. That's an important shift. The 1970s conspiracy thriller was almost entirely a story about men. The X-Files made the skeptic, the scientist and frequently the hero a woman working inside the same institution.
Watching the lineage
If you want to see where the show came from, watch The Parallax View and All the President's Men back to back, then the X-Files pilot. The flashlights and the aliens are new. The framing, the darkness and the distrust are not.