While working at the newspaper, Argento started screenwriting. His most notable work was for Sergio Leone, collaborating with Bernardo Bertolucci on the story for the Spaghetti Western classic Once Upon a Time in the West. Soon after its release in 1969, Argento wrote and directed his first movie, The Bird with the Crystal Plumage, which was released in 1970 and was a major hit in Italy.
His directing style was influenced by Mario Bava, Riccardo Freda, Sergio Leone, Alfred Hitchcock, Michelangelo Antonioni, and Federico Fellini.
Argento directed two further successful thrillers, The Cat of Nine Tails (1971) and Four Flies on Grey Velvet (1972). Alongside The Bird with the Crystal Plumage, these initial three films are frequently referred to as Argento's "animal trilogy". The director then turned his attention away from giallo movies, filming two Italian TV dramas and a period comedy (Five Days in Milan) in 1973 before returning to thrillers with 1975's Deep Red, frequently cited by many critics as the best giallo ever made. The film made Argento famous internationally, and inspired a number of other directors to work in the genre (John Carpenter has frequently referred to the influence Argento's early work had on Halloween). It also marked the start of Argento's long creative relationship with the Italian rock group "Goblin".
In-between the two "mothers", in 1978 Argento collaborated with George Romero on Dawn of the Dead, earning a producer credit on the Zombie classic. Argento oversaw a variant Italian edition of Dawn of the Dead, cut and structured somewhat differently with more "Goblin" music overlayed throughout.
After Inferno, Argento returned to more conventional giallo with Tenebrae (1982), then attempted to combine giallo and supernatural fantasy together in Phenomena aka Creepers (1985), which was one of Jennifer Connelly's first movies. Phenomena also showed Argento's predilection for using new technology, with its many prowling Steadicam shots. Both of these movies received a lukewarm reception upon release (although each has been re-appraised retrospectively).
Argento subsequently took a break from directing to write two screenplays for Mario Bava's son Lamberto Bava, Demoni (1985) and Demoni 2 (1986).
It is widely accepted that his 1990s career and onwards has failed to live up to his golden period between Deep Red and Opera. Despite a disappointing collaboration with George A. Romero on an Edgar Allan Poe anthology entitled Two Evil Eyes (1990), an unsuccessful stab at a mainstream Hollywood production (Trauma (1993)) and a disastrous version of Phantom of the Opera (1998) which lost him many fans, he continued to innovate: for example, his 1996 The Stendhal Syndrome, in which a policewoman (played by Argento's daughter, Asia) who suffers from a dramatized version of the illness is trapped by a Serial killer in an abandoned warehouse, was the first Italian film to use Computer-generated imagery (CGI). Furthermore, the opening of The Stendhal Syndrome was shot in Florence, at Italy's famed Uffizi Gallery, Argento being the only director ever granted permission to shoot there.
Many saw 2001's Sleepless, deliberately designed as a "comeback movie" with its strong giallo theme and numerous references to his earlier work, as a step back in the right direction. However, Argento's follow-up, 2004's The Card Player, a giallo about a killer whose murders are conducted during Internet poker matches with the Rome police, earned a mixed reception: fans appreciated the techno music score composed by ex-Goblin member Claudio Simonetti, but felt the film was too mainstream, with little of Argento's usual flourish.
2005 saw the TV broadcast of Argento's Do You Like Hitchcock?, in which the Italian horror-meister finally paid homage to Alfred Hitchcock after decades of being compared to him by critics.
Argento's works always include a profusion of allusions (both obscure and obvious) to other films, literature ranging from the Greek classics to current popular novels, politics, film/literary theory, as well as his own films. This dense network of allusions, combined with his notorious negligence of Plot, his bizarrely detailed mise-en-scenes, his obsession with gore-filled death scenes, and his unpredictable and roaming camera angles, has proven particularly resistant to critical interpretation.
Little 'serious' academic work on Argento has been published; until recently, the two most notable publications on Argento were Maitland McDonagh's critically acclaimed auteur study, Broken Mirrors/Broken Minds: The Dark Dreams of Dario Argento, and, to a lesser extent, a collection of promotional stills, Poster art and somewhat facile critical essays, edited by Chris Gallant, entitled Art of Darkness. British journalist Alan Jones recently published Profondo Argento, a useful compendium of set reports, interviews and biographical detail manages to further illuminate the personality behind Argento's movies.
While critical work on Argento is unfortunately limited (and often out of print), the director has acquired a cult fan base in Italy and the rest of the world; film reviews and interviews are regular subjects of interest in fanzines and internet discussion groups.
One significant factor in Argento's lack of recognition in the United States is the generic boundaries which do not recognize the 'giallo' form - his films are often marketed as "slasher trash" or simply "horror", only occasionally making the art house or college cinema circuits.