One faction that Mr. Segel and the filmmakers are unlikely to ever win over, though, is the David Foster Wallace Literary Trust, Wallace’s widow, Karen Green, and his closest editors. In April 2014, the trust issued a withering objection to the film, saying Wallace would never, if alive, have agreed to it. That the trust could not stop the film — certain privacy rights do not extend to the dead or to their estates — only heightened their ire.

The film’s warm reviews have not swayed them an inch. Michael Pietsch, Wallace’s longtime editor, wrote in an email that Wallace’s writing made clear his anguish about being a public figure and “his overwhelming anxiety about being on the wrong side of the screen.” Alex Kohner, the co-trustee and lawyer for the trust, said that when Wallace agreed to be interviewed by Mr. Lipsky, he did not consent to be portrayed in a film. Mr. Kohner also said he contacted the producers as soon as they learned about the film, but that the “objections fell on deaf ears.”

“In my opinion it is unlikely that the filmmakers could have legally capitalized on the unpublished interview and David’s good name if he were alive,” Mr. Kohner wrote by email. “Regardless of whether or not this film has entertainment value we question the ethics of their actions.”

Via a spokeswoman, the producers said they had been under the impression that “Wallace’s camp” knew Mr. Lipsky’s book was to be made into a film and that the producers had not known of the opposition until shortly before production began, when it was too late to turn back. “We are very proud of the film, and as deep admirers of his work, were always committed to honoring the memory of David Foster Wallace,” three of the five producers, David Kanter, James Dahl and Matt DeRoss, said in a statement.

Image Jonah Hill and Mr. Segel, in floral prints for “Forgetting Sarah Marshall.” Credit... Glen Wilson/Universal Pictures

Mr. Lipsky did not respond to repeated interview requests and, at the last minute, said through a representative that he was on a deadline and had no time to speak. Mr. Ponsoldt would not address the trust’s grievances, but a person close to him said he had not been aware of them until late in the process and felt terribly about them. Donald Margulies, the Pulitzer Prize-winning playwright who wrote the screenplay, said the objections made everyone involved feel badly. “We’ve approached this with such, we think, humanity,” he said.