Carrey's comedy "Yes Man" opened at No. 1 with $18.2 million in ticket sales, while Smith's drama "Seven Pounds" came in second with $16 million, according to studio estimates Sunday.
Debuting at No. 3 with $10.5 million was Matthew Broderick's animated family flick "The Tale of Despereaux."
The new movies arrived in theaters Friday just as storms pounded the Northeast.
"Those markets back east just got hammered," said Chris Aronson, distribution executive for 20th Century Fox, whose sci-fi saga "The Day the Earth Stood Still" slipped from No. 1 to No. 4 with $10.2 million. The movie starring Keanu Reeves raised its 10-day total to $48.6 million.
"Yes Man," released by Warner Bros., stars Carrey as a loser who turns his life around by subscribing to a philosophy of saying "yes" to everything. Sony's "Seven Pounds" casts Smith as a mysterious IRS agent doing good deeds for strangers, and Universal's "Tale of Despereaux" features Broderick as the mouthpiece for a tiny mouse on a heroic mission.
In limited release, Mickey Rourke's acclaimed drama "The Wrestler" had a heavyweight debut, taking in $209,474 in just four theaters for a whopping average of $52,369.
By comparison, "Yes Man" played in 3,434 theaters and averaged $5,288 per theater, while "Seven Pounds" opened in 2,758 theaters and averaged $5,801 per theater. The No. 3 film "The Tale of Despereaux" played in 3,104 theaters and grabbed $3,385 per venue.
The film released by Fox Searchlight stars Rourke as a former wrestling champion struggling for one last taste of past glory. The comeback theme of "The Wrestler" parallels Rourke's real life, with the actor in the running for an Academy Award nomination after his bad boy behavior virtually ruined his career in the late 1980s and early 1990s.
"Yes Man" played in 3,434 theaters and averaged $5,288 per theater, while "Seven Pounds" opened in 2,758 theaters and averaged $5,801 per theater. The No. 3 film "The Tale of Despereaux" played in 3,104 theaters and grabbed $3,385 per theater.
While winter came in with a bang, Hollywood's solid year was going out with a whimper. The overall box office plunged for the second straight weekend as this season's pre-holiday offerings continued to lag far behind the strong finish provided by such 2007 hits as Smith's "I Am Legend" and "Alvin and the Chipmunks."
The top 12 movies took in $82.8 million, down 44 percent from the same weekend last year, when "National Treasure: Book of Secrets" led with $44.8 million.
The last two ho-hum weekends have hindered Hollywood's shot at breaking the domestic revenue record of $9.7 billion set last year. Revenues through Sunday were at $9.24 billion, virtually even with 2007 through the same date, according to box-office tracker Media By Numbers.
Given the sour economy, studio executives generally are satisfied with this year's results. Hollywood tends to ride out recessions with solid business, since movies are relatively inexpensive compared to entertainment options such as concerts or sports events.
"The movie business may be recession-proof, but this weekend, it's not weather-proof," said Paul Dergarabedian, president of Media By Numbers.
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. "Yes Man," $18.2 million.
2. "Seven Pounds," $16 million.
3. "The Tale of Despereaux," $10.5 million.
4. "The Day the Earth Stood Still," $10.2 million.
5. "Four Christmases," $7.7 million.
6. "Twilight," $5.2 million.
7. "Bolt," $4.3 million.
8. "Slumdog Millionaire," $3.2 million.
9. "Australia," $2.3 million.
10. "Quantum of Solace," $2.2 million.