The episode is only eclipsed by his Election Eve visit from President Obama in 2008, which garnered 3.6 million-viewer record, said The Hollywood Reporter.
Stewart, 52 hosted the Comedy Central show since 1999. In his last episode, he made an impassioned final speech warning his audience against falsehood that is "designed to obscure and distract".
The episode has already added one million full-episode streams online.
Among adults 18-49, Stewart averaged 1.8 million viewers.
Former correspondents, including Oscar-nominated actor Steve Carell, of the show lined up to bid him farewell while recalling his debt to their careers and the legacy that he leaves behind.
"The Daily Show" will go on a break now, with 31-year-old Trevor Noah taking the host gig when it returns on September 28.