The film's plot involves the children's charity "Childreach". Since 2002, the year of the film's release, the organization has referenced the film and featured its poster in its literature for prospective child sponsors.
Once the filmmakers bought the rights to the Louis Begley novel, they kept the title and the main character but changed just about everything else. In the book, the main character lived in the Hamptons and his daughter was about to marry a lawyer. One element Alexander Payne considered keeping from the novel was Warren Schmidt's anti-Semitism, which would have been kept by having Dermot Mulroney's character Randall be Jewish (as the lawyer who Jeanie was getting read to marry in the book was), but Payne decided the movie would work better if Schmidt was not a bigot.
A scene that echoes Jack Nicholson's famous diner scene in Five Easy Pieces (1970) (his exchange with the waitress) was in an early cut of the movie in which Schmidt concedes in a cowardly fashion to the dictates of the waitress. Though the preview audience went wild over it, director Alexander Payne cut it from the final film because he felt that the scene was too much of a pointed reference to Nicholson's iconography and that something so referential took the audience out of the film.
When asked about the film, Louis Begley said he enjoyed it and thought it kept the spirit of the novel alive, even though the film changed almost everything from the novel. The one thing he said he missed was the removal of Schmidt's Hispanic girlfriend, a key character in the novel that was dropped in the film version.
Two sequels to About Schmidt were written by Louis Begley: Schmidt Delivered and Schmidt Steps Back. Alexander Payne, who has the film rights to the series, has declined to produce either as he avoids making sequels of his work (he took a similar stance on his other film Sideways, where he declined to produce either of the sequel novels written by Rex Pickett).
Len Cariou plays Ray and Angela Lansbury narrates the Childreach commercial. They played Sweeney Todd and Mrs. Lovett respectively in the original Broadway version of the musical "Sweeney Todd: The Demon Barber of Fleet Street."
The movie theater that Warren drives by before he goes to the museum to look at the arrowheads is the Pioneer 3 in Nebraska City, Nebraska. The "museum" is a Civil War museum in the same town, just down the street.
Alexander Payne said the screenplay was a hybrid of both the novel About Schmidt and his own original screenplay, The Coward, which he wrote while a student at UCLA. The title, main character and overall plot and theme were kept from About Schmidt, while The Coward was a story about a closed-minded man having a spiritual awakening as he closes in on the end of his life.