Hancock earned $7.67m (Y830m) on 328 screens, including grosses from previews last weekend.
The opening eclipses Will Smith's previous release, I Am Legend, which took in $5.35m on 422 screens last December. SPE is aiming for a Y4bn ($37m) final tally. The company recorded its best year ever in the territory last year with earnings of $150.46m (Y16.27bn).
In second place, the first installment in NTV's mega-budget 20th Century Boys trilogy opened on 310 screens, taking in $5.78m (Y625.6m) for a high $18,660 per screen average. Distributor Toho expects earnings to surpass Y5bn ($46.23m). The trilogy is budgeted at $55m.
The film had its world premiere in Paris on August 19 and has already been sold to around 20 territories including France, the UK, Australia and Korea, where it will have the widest opening ever for a Japanese live-action film on September 11. The second and third chapters will open in six month intervals. Naoki Urasawa's epic manga series on which the film is based has sold over 20 million copies.
The success of both films signaled the end of the younger fare that dominated the summer period, led by Ponyo.
Ponyo has amassed $117.42m (Y12.7bn) since its July 19 opening as the most successful domestic release since Hayao Miyazaki's own Howl's Moving Castle in 2004. The film had its international premiere in Venice on August 30.