In one scene the dog starts mimicking Jack Nicholson by stepping over the cracks in the sidewalk. The filmmakers accomplished this by placing little obstacles on the cracks so that the dog had to step over them. They then removed the obstacles digitally in post-production.
At the 1998 Oscar ceremony, when his name was announced as the winner of the Best Actor award, Jack Nicholson ascended to the podium by carefully stepping over the cracks between the tiles on the stage, in imitation of his character, Melvin Udall. Nicholson dedicated his Oscar to his A Few Good Men (1992) co-star J.T. Walsh who had died shortly before the Academy Awards in 1998.
Jack Nicholson and Helen Hunt won the Best Actor and Best Actress Oscars respectively for this film, while Greg Kinnear was nominated for Best Actor in a Supporting Role. Nicholson is the only actor to date (2017) to ever star in a film for which he would win the Oscar for Best Actor that would also receive a Best Actress Oscar, and also be nominated for Best Actor in a Supporting Role. The previous one was One Flew Over the Cuckoo's Nest (1975) in which Nicholson and Louise Fletcher won Oscars for Best Actor and Actress, while Brad Dourif was nominated for Best Actor in a Supporting Role.
An earlier version of the script was called "Old Friends". It was listed as one of the best unproduced screenplays by Movieline Magazine, and had Kevin Kline and Mike Newell attached at one point to star in and direct it, respectively.
The song "Always Look on the Bright Side of Life" was written by Eric Idle as the ending melody for Monty Python's Life of Brian (1979). It has become a favorite in the UK for footballers, and even funerals.
At the end of this film, when the credits begin to roll, the song "Always Look on the Bright Side of Life" performed for this film by Art Garfunkel, begins to play. Jack Nicholson and Art Garfunkel appeared in Carnal Knowledge (1971).
When Melvin and Carol are in the restaurant in Maryland, the singer in the background is Danielle Brisebois, perhaps most recognisable for having played Archie and Edith's niece Stephanie on All in the Family (1971). The song she is singing is Fallen, which was the love theme from Pretty Woman (1990).
Entertainment Weekly listed the film under its original title, "Old Friends", in their fall movie preview from the August 22/29, 1997 issue. James L. Brooks felt that the title "just doesn't say it for me." Brooks considered several other titles, including "Rock Bottom" and "The Bright Side of Life", but couldn't best the original title. Eventually, the film earned the new title, in time for posters and trailers to be released.
This film would technically be the second consecutive film to feature Jack Nicholson and Helen Hunt. The latter starred in Twister (1996), which featured a scene where a drive-in theater was playing The Shining (1980), starring Nicholson.