Directed by Sean Penn, "Into the Wild" also was nominated for performance by its overall cast, along with the Western "3:10 to Yuma," the crime sagas "American Gangster" and "No Country for Old Men," and the musical "Hairspray."
Conspicuously absent from the guild field was the British romantic melodrama "Atonement," which was shut out after leading the Golden Globe nominations a week earlier with five nominations.
Hirsch was nominated as best actor for his role as fierce idealist Christopher McCandless, a recent college graduate who abandoned a cozy life and took to the road for two years, coming to a tragic end in the Alaska wilderness in the 1990s.
Other best-actor nominees were George Clooney as a conscience-stricken attorney in "Michael Clayton," Daniel Day-Lewis as an oil baron in "There Will Be Blood," Ryan Gosling as a social misfit with a life-size doll for a girlfriend in "Lars and the Real Girl" and Viggo Mortensen as a Russian mobster in "Eastern Promises."
Nominated for best actress were Cate Blanchett as the British monarch in "Elizabeth: The Golden Age," Julie Christie as a woman fading from Alzheimer's in "Away From Her," Marion Cotillard as singer Edith Piaf in "La Vie En Rose," Angelina Jolie as journalist Mariane Pearl in "A Mighty Heart" and Ellen Page as a whipsmart pregnant teen in "Juno."
Blanchett also was nominated for supporting actress as an incarnation of Bob Dylan in "I'm Not There," a fanciful film biography featuring six different performers playing variations of the musician.
Though critically acclaimed, "Into the Wild" was shut out on acting nominations for the Golden Globes. Along with Keener and Holbrook, whose characters become surrogate family for Hirsch's McCandless, the guild supporting lineup included two others overlooked by the Globes: Tommy Lee Jones as a wayworn sheriff in "No Country for Old Men" and Ruby Dee as mother to Denzel Washington's crime overlord in
Jones will compete against "No Country for Old Men" co-star Javier Bardem, who may be the closest thing to an Oscar front-runner at this point for his electrifying performance as a ruthless killer tracking a missing cache of drug money.
Guild awards will be presented Jan. 27 in a ceremony televised on TNT and TBS.
Unlike the Academy Awards and the Golden Globes, which face turmoil caused by striking Hollywood writers, the guild awards look as though they can come off as planned. With actors showing strong solidarity on strike issues, SAG has reached an agreement with the Writers Guild of America for one of its members to write the ceremony.
If the strike that began last month lingers, though, the Globes on Jan. 13 and Oscars on Feb. 24 face possible protests by striking writers and stars who may stay away rather than cross picket lines.
The Writers Guild rejected a request from Globe organizers to allow striking writers to work on that show. Oscar organizers have not yet asked for a similar waiver but face the same prospect.
Along with the Golden Globes and other film honors, the guild picks help sort out favorites and other possible nominees for Hollywood's big prizes, the Oscars, whose nominations come out Jan. 22.
Actors who are guild winners often go on to win Oscars. Last year, Helen Mirren for "The Queen" and Forest Whitaker for "The Last King of Scotland" were both guild and Oscar winners, as was supporting-actress Jennifer Hudson for "DreamGirls."
The guild's supporting-actor winner, Eddie Murphy for "DreamGirls," lost at the Oscars to Alan Arkin for "Little Miss Sunshine."
"Little Miss Sunshine" won the guild prize for overall acting ensemble, SAG's equivalent of a best-picture honor, while "The Departed" won best picture at the Oscars.
Film and TV nominees were chosen by two groups of 2,100 people randomly chosen from the guild's 120,000 members. The guild's full membership is eligible to vote for winners.
By DAVID GERMAIN