It's Eastwood's best opening ever, topping the $18 million his "Space Cowboys" made in 2000.
In what Eastwood, 78, has said may be his last starring performance, he plays a disgruntled Korean War veteran who reluctantly comes to the aid of his immigrant neighbors.
The National Board of Review dubbed Eastwood's performance the best for an actor in 2008, and his song "Gran Torino" was nominated for a Golden Globe at Sunday's awards ceremony.
"Gran Torino," which Eastwood also directed, was previously in limited release for four weeks. It jumped from 84 theaters to 2,808 this weekend after boasting very high theater averages.
"At this stage of his career, I think it's remarkable," said Dan Fellman, head of distribution at Warner Bros., which released "Gran Torino." "There are a lot of younger people that can identify with him in a role like this that maybe haven't seen him in a role like this since `Dirty Harry."'
Eastwood stole the box-office bouquet from Anne Hathaway and Kate Hudson. Their wedding comedy "Bride Wars," released by 20th Century Fox, came in second with $21.5 million. The horror film "The Unborn" from Universal Pictures followed with $21.1 million in its debut.
"Marley & Me," the Jennifer Aniston and Owen Wilson's family dog tale that topped the box office the last two weekends, fell to fourth with $11.4 million and a cumulative total of $124 million for the 20th Century Fox film.
While awards season was heating up, most of the major contenders had solid numbers, though mostly in limited release.
Paramount Vantage's "The Curious Case of Benjamin Button" took in $9.4 million in its third week of release, bringing its total closer to the century mark with $94 million.
Focus Features' "Milk," Paramount Vantage's "Revolutionary Road" and Fox Searchlight's "The Wrestler" all with awards hopes at the Globes and beyond were among the best performers in screen average. Each hopes to continue to build momentum as the Oscars near.
"Defiance," in its second week of limited release, led with a robust $33,000 screen average. "Defiance" stars Daniel Craig in the story of Jewish brothers who form a band of freedom fighters against the Nazis in Eastern Europe.
Fox Searchlight's underdog hit "Slumdog Millionaire" added $3.7 million to its total of $34 million.
The success of "Gran Torino" could boost Eastwood's awards chances. The film was largely overlooked by the Globes, but the Oscars have long supported Eastwood's directorial efforts and awarded his "Million Dollar Baby" best picture in 2005.
"This will raise its profile in a very profound way," said Paul Dergarabedian, president of box-office tracker Media by Numbers. "Certainly `Gran Torino' is in an excellent position. It's a textbook case of releasing a film in limited, nurturing it for about a month and unleashing it upon the world in a wide release and really capitalizing on that."
That audiences remain so eager to see Eastwood on the screen suggests to Fellman that he should rethink any acting retirement.
"Clint has said this is the last time he's going to be in front of the lens. I hope he reconsiders after this," Fellman said.
Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Media By Numbers LLC. Final figures will be released Monday.
1. "Gran Torino," $29 million.
2. "Bride Wars," $21.5 million.
3. "The Unborn," $21.1 million.
4. "Marley & Me," $11.4 million.
5. "The Curious Case of Benjamin Button," $9.4 million.
6. "Bedtime Stories," $8.6 million.
7. "Valkyrie," $6.7 million.
8. "Yes Man," $6.2 million.
9. "Not Easily Broken," $5.6 million.
10. "Seven Pounds," $3.9 million.