Timothy Hutton's father, actor Jim Hutton, died just months prior to filming. However, Hutton stated he did not use his mourning as a basis for Conrad's depression. Also, actress Mary Tyler Moore's only son, Richie Meeker, accidentally shot himself a month after the film's release. Moore was also separated from her husband, producer Grant Tinker, during filming.
According to the Entertainment Weekly article on the making of this movie, Mary Tyler Moore was cold, snobbish and uncommunicative with Timothy Hutton on the set, to assist her in mastering the aloofness so essential to her character.
Mary Tyler Moore was shocked by Robert Redford's offer that she portray Beth, especially given her sunny, warm and highly connective screen persona in Dick van Dyke Show (1961), Mary Tyler Moore (1970), and elsewhere. Moore stated that, in response to her surprise, Redford confided that he'd had her in mind for the role since the first time he'd read the novel. Viewers were in turn surprised by Moore's performance, though she received critical praise.
Elizabeth McGovern was a student at Juilliard during filming. The school permitted her to do the film on the condition that she leave for Chicago each Friday night and return on Sunday, filming only on Saturdays. It was the first time Juilliard had ever permitted a student to make a film during a school term.
The final scene in the dining room between Calvin and Beth was originally shot with both Donald Sutherland and Mary Tyler Moore on location. However, during editing, Sutherland thought that he had Calvin crying too much, ruining the scene. So, he and director Robert Redford reshot his scenes on a partial set recreated to look like the dining room. Since Moore, who was doing theater work in New York, was unable to return for the reshoot, Redford read her lines off camera for Sutherland to respond to.