Kutcher's debut as Sheen's replacement in the CBS sitcom "Two and a Half Men" was seen by 27.8 million people on Monday. The Nielsen Co. said Tuesday that was more than any other episode in the show's first eight seasons, when Sheen was the star.
The sitcom's previous best came in May 2005 following the final episode of "Everybody Loves Raymond."
Meanwhile, Sheen appeared Monday as the "victim" of a Comedy Central roast that reached 6.4 million people. That is the second most-watched telecast in the cable network's history, behind only Jeff Dunham's holiday special in 2008.
The season-opening episode of "Two and a Half Men," television's most popular comedy, was much anticipated. Producers kept it a secret how they would kill off Sheen's character and introduce Kutcher's.
Sheen had been fired from the show last season for drug use and erratic behavior. He launched a weekslong tirade against his bosses, including show creator Chuck Lorre, and Lorre got revenge in Monday's episode.
Sheen's Charlie Harper character was killed when he was hit by a subway train in Paris.
Meanwhile, Kutcher appeared as an Internet billionaire unsuccessful in a suicide attempt over a crumbled relationship. He fell right into the show's randy ways, picking up two women during a bar visit that same night.
The success of "Two and a Half Men" gave a boost to the premiere of CBS' new comedy "2 Broke Girls" that followed it. That show had an audience of 19.2 million, the largest audience for a fall sitcom premiere since "Inside Schwartz" a decade ago.
The veteran CBS comedy "How I Met Your Mother" had its best season premiere numbers. By contrast, the season premiere of "Hawaii Five-0" had a relatively modest audience of 12 million.