Rookie filmmaker Sam Mendes, better known for helming such stage as the Tony-winning Cabaret revival, beat out several of his fellow Academy Award contenders to claim the top DGA prize and position his tragicomic suburban satire for a likely sweep come Oscar time.
"Thank you to the studio for giving a bloke from England a movie about the American suburbs and letting me make the movie I wanted to make," Mendes said.
The other nominees were Being John Malkovich's Spike Jonze, The Green Mile's Frank Darabont, The Insider's Michael Mann and Sixth Sense helmer M. Night Shyamalan.
The DGA Award, voted on by Hollywood's filmmaker union, makes Mendes a virtual lock for the Best Director statuette to be presented March 26 (Overall, American Beauty is up for eight Oscars). Since the inception of the Guild award in 1949, only four winners have not gone onto Academy Award glory: Anthony Harvey (ignored on Oscar night for 1968's The Lion in Winter); Francis Ford Coppola (for 1972's The Godfather); Steven Spielberg (for 1985's The Color Purple); and Ron Howard (for 1995's Apollo 13).
And it's rare when the Best Director doesn't helm the Best Picture (last year was an exception, with Spielberg taking home the directing Oscar for Saving Private Ryan, but losing out in the best film race to Shakespeare in Love).
Spielberg, who won the DGA last year for Ryan and whose DreamWorks studio released American Beauty, was on hand to present this year's trophy to Mendes.
On Saturday, Spielberg also collected the DGA's ultimate props, the Lifetime Achievement Award for a body of work that includes such latter-day classics as Schindler's List, Close Encounters of the Third Kind, Jaws, E.T. and Raiders of the Lost Ark.
Until this year, the Lifetime Achievement Award was known as the D.W. Griffith Award, after the pioneering silent-film director. In a controversial move, the Guild dropped Griffith's name because of his racist portrayal of blacks in several films, including his masterpiece, Birth of a Nation.
By winning the award, Spielberg joins a list of filmmaking legends, including Cecil B. DeMille, Alfred Hitchcock and Stanley Kubrick.
Other winners at the 52nd annual DGA Awards included Mick Jackson (Tuesdays with Morrie) in the TV-movie category; David Chase for prime-time drama for the pilot episode of The Sopranos; Sports Night's Thomas Schlamme in the TV comedy category for the sitcom's "Small Town" episode; Deannie A. Gordon for TV Musical-Variety Tracey Takes on...End of the World; Days of Our Lives helmers Herbert D. Stein and Roger W. Inman in the TV serial category; and Amy Schatz for children's show for HBO's Goodnight Moon & Other Sleepytime Tales.