Distributor Sony calls those results "unprecedented" for a Tuesday in October. The film chronicles Jackson's concert preparations for what would have been 50 comeback concerts in London.
Photos: "This Is It" Hits Hollywood
Complete Michael Jackson Coverage
"This Is It" opened in 99 countries and expanded its release Wednesday. Sony has already called Wednesday box office numbers "explosive" and says matinees alone have doubled Tuesday night's haul.
The film show Jackson preparing for a marathon concert stand in London that never happened.
The pop star died in June at age 50. His death has been ruled a homicide.