The PG-rated comedy, starring James as a portly shopping center security guard who tries to foil a bank heist, made $33.8 million in its first three days and is expected to reach $40 million over the Martin Luther King Jr. holiday weekend.
That far surpasses expectations, said Rory Bruer, president of worldwide distribution for Sony, which released the movie.
"We had a lot of screenings as well as tracking that was good on it. We were hopeful we could do in the range of $25 million for four days and that would have been a terrific result for us. But now it looks like we're going to do $40 million for four days, and that is just, like, a 'wow' number," Bruer said Sunday. "It totally speaks to just how much audiences love Kevin James, No. 1, and how hard he worked to promote this film."
After proving his value as a sidekick to Will Smith in "Hitch" and Adam Sandler in "I Now Pronounce You Chuck & Larry," James shows here he can also be a reliable leading man, said Paul Dergarabedian, president of the box-office tracker Media by Numbers.
"In these tough, recession-laden times, you'd think people wouldn't want a movie that's based around a mall, but they totally do," Dergarabedian said. "Kevin James has that everyman quality. People relate to him."
Last week's No. 1 movie, "Gran Torino," dropped to second place but only by 25 percent. The Warner Bros. drama, directed by and starring Clint Eastwood as a bigot who becomes a reluctant neighborhood hero, made $22.2 million this weekend for a cumulative gross of $73.2 million.
Among other new releases, the Lionsgate horror flick "My Bloody Valentine 3-D" opened at the No. 3 spot with $21.9 million.
Fourth was "Notorious," about slain rapper Notorious B.I.G., which made $21.5 million. That's the biggest opening ever for Fox Searchlight, which previously released such critical darlings and crowd-pleasers as "Juno" and "Little Miss Sunshine."
"It's a very high quality film, and it's a compelling look at a compelling cultural icon who, like many cultural icons, left way too early but left an indelible mark on society," said Chris Aronson, senior vice president of domestic distribution for 20th Century Fox.
The week's other new wide release, the Paramount family comedy "Hotel for Dogs," opened at No. 5 with $17.7 million. Over at Paramount Vantage, "Defiance," based on the true story of Jews who survived the Holocaust by forming a community in the forests of Belarus, did well in its nationwide expansion. The movie starring Daniel Craig and Liev Schreiber made $9.8 million to reach the No. 8 spot.
The big winner at last weekend's Golden Globes, "Slumdog Millionaire," crept into the No. 10 spot with $5.9 million. The Fox Searchlight drama about a teen who rises from the slums of Mumbai to become a game show champion won awards for best picture, director (Danny Boyle), screenplay and original score.
Now playing in limited release in 582 theaters, "Slumdog" will expand to more than 1,200 theaters next weekend following Thursday's Academy Award nominations. It's made a total of $42.7 million in 10 weeks.
"You can see the impact of the Golden Globe winnings and, also, people are just discovering this film so we're able to keep growing our audience," said Richard Shamban, vice president of theatrical distribution for Fox Searchlight.
Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Media By Numbers LLC. Final figures will be released Tuesday.
1. "Paul Blart: Mall Cop," $33.8 million.
2. "Gran Torino," $22.2 million.
3. "My Bloody Valentine 3-D," $21.9 million.
4. "Notorious," $21.5 million.
5. "Hotel for Dogs," $17.7 million.
6. "Bride Wars," $11.75 million.
7. "The Unborn," $9.8 million.
8. "Defiance," $9.2 million.
9. "Marley & Me," $6.3 million.
10. "Slumdog Millionaire," $5.9 million.