The tale of a reluctant, boozy superhero who has to change his ways also stars Jason Bateman and Charlize Theron and had been expected to finished in the $105m-plus range.
Hancock is Smith's fifth picture to open at number one over the July The Fourth weekend but still wasn't enough to prevent a mild 4% slip against the same period last year, when Transformers launched on $70.5m over three days and took $146.6m over six.
Overall this weekend's top 12 pictures combined for $158.7m and the summer to date has generated $2.22bn, which according to reports puts this season approximately 2% ahead of last year's record summer.
Everything else just moved down one place. Buena Vista's Wall-E ranks second and added $33.4m for $128.1m after two weekends, while Universal's action thriller Wanted in third added $20.6m for $90.8m after the same amount of time.
Get Smart is bearing down on $100m for Warner Bros and ranks fourth on $98.1m after three weekends, while DreamWorks Animation's Kung Fu Panda, released through Paramount and placing fifth in its fifth weekend, stands at $193.4m. Indiana Jones And The Kingdom Of The Crystal Skull ranks seventh after seven on $306.6m.
Picturehouse's period drama Kitt Kittredge: An American Girl starring Abigail Breslin expanded in its third weekend and climbed 15 places to eighth on $6.1m. Paramount's The Love Guru fell out of the top ten in its third weekend and ranks 11th on a disapointing $29.3m.
Next weekend's wide releases are: Fox's comedy Meet Dave starring Eddie Murphy; Universal's comic book adaptation Hellboy II: The Golden Army from Guillermo del Toro; and Warner Bros' adopted New Line production Journey To The Centre Of The Earth 3D with Brendan Fraser.
Estimated Top 10 North America Jul 4-6, 2008
Film (Dist)/Int'l dist/Est wkd gross/Est total to date
1 (-) Hancock (Sony) SPRI $66m $107.3m
2 (1) Wall-E (Buena Vista) WDSMPI $33.4m $128.1m
3 (2) Wanted (Universal) UPI $20.6m $90.8m
4 (3) Get Smart (Warner Bros) WBPI $11.1m $98.1m
5 (4) Kung Fu Panda (Paramount) PPI $7.5m $193.4m
6 (5) The Incredible Hulk (Universal) UPI $4.9m $124.9m
7 (7) Indiana Jones And The Kingdom Of The Crystal Skull (Paramount)
PPI $3.9m $306.6m
8 (23) Kitt Kittredge: An American Girl (Picturehouse) NLI $3.6m $6.1m
9 (9) Sex And The City (New Line/Warner Bros) NLI $2.3m $144.9m
10 (10) You Don't Mess With The Zohan (Sony) SPRI $2m $94.8m