The parts of Dorothy and Jerry were originally written for Winona Ryder and Tom Hanks. Hanks was unable to commit to the project due to his work on That Thing You Do! (1996). Ryder was able to commit, but when screen tests were done with Tom Cruise, they "looked like brother and sister" when standing together.
The story for Jerry Maguire is reportedly based on real-life Orange County agent Leigh Steinberg (who actually makes a cameo in the film as Troy Aikman's agent, which he was in real-life too). Steinberg's ex-partner David Dunn tried to lure away many of Steinberg's clients, just as Jay Mohr's Bob Sugar does in the film.
The scene in which Jerry and Ray are talking in the living room for the first time, was completely adlibbed. Director Cameron Crowe wanted to create a genuine "feel" between the two and did so by not having a written dialogue for that particular scene.
Two Paul McCartney instrumentals are used in the movie, "Momma Miss America" (during the airport montage) and "Singalong Junk" (during Jerry and Dorothy's first kissing scene on the porch), both from the 1970 album "McCartney". Cameron Crowe received McCartney's permission without ever having met him, instead sending a tape of the film to the latter's office. The two would actually meet for the first time five years later in L.A., and the result of that meeting was McCartney composing the title song to Crowe's movie Vanilla Sky (2001), which earned an Oscar nomination for Best Original Song.
Cameron Crowe wanted his hero, legendary film director Billy Wilder, to play Dicky Fox. Wilder had agreed to think about it, but on the first day of filming, Wilder refused to play the role. So Crowe took Tom Cruise to Wilder's office to try to convince him, and Wilder still said no. Later, Crowe and Wilder became friends and Crowe wrote a book about Wilder's life.
When Dorothy and Ray drop off Jerry at the airport and look at the family saying goodbye (a mother and child are seeing off the father), the three people shown are the stand-ins for Tom Cruise, Renée Zellweger and Jonathan Lipnicki who worked on the film.
Cameron Crowe offered the Dorothy Boyd role to Janeane Garofalo, if she could lose weight, but after trimming down, she learned that Renée Zellweger had won the part instead in what was to become a career-launching smash hit.
The Cardinal - Cowboy game at the end of the movie was actually an ABC Monday Night Football game played on Monday December 25, 1995. In the movie the Cardinals won, in real life the Cowboys won 37 - 31.
In the elevator scene when Jerry and Dorthy spot a man signing to his girlfriend and Dorothy translates it as "You complete me", the man appears to be using Pidgin sign (basically American Sign Language signs in English word order) or possibly a form of Manually Coded English. What he literally says is "You make me feel whole."
At the end of the movie, while Rod Tidwell is being interviewed on TV, Jerry Maguire is congratulated by a lady. She is the Winter Olympic champion Katarina Witt. She is seen standing next to Leigh Steinberg, the inspiration for the the title character. Leigh Steinberg introduces Jerry to Troy Aikman in the movie.
Cuba Gooding Jr.'s character in the film is named "Rod Tidwell" and played for the Arizona Cardinals football team. Tidwell's name may be inspired by Bill Bidwell, the owner of the team for 45 years who oversaw the team's move from St. Louis to Arizona. He is thanked in the credits.
Renée Zellweger's famous line "You had me at 'hello'" served as the inspiration behind Kenny Chesney's 1999 single with the similar name "You Had Me From Hello." In 2005, Zellwegger married Chesney, only to have it annulled after four months.
Because Cameron Crowe took so long writing the screenplay, he felt his original choice to play the title character - Tom Hanks - was too old to play the part by the time the film was ready to be made. Besides, Hanks had just won back-to-back Oscars and was in the midst of directing That Thing You Do! (1996).
When Cuba Gooding Jr. first read for his part for the studio, he did so with Robin Williams, assuming that Williams was going to be playing the title role. However, Tom Cruise had already been hired and Williams was simply substituting as a favor.