In the scene near the end where Spencer Tracy gives his memorable soliloquy, Katharine Hepburn can be seen crying in the background. This was not acting: she knew how gravely ill her longtime lover was and was moved by his remarks about how true love endures through the years.
This movie was still showing in theaters at the time Martin Luther King was assassinated. Originally, there was a line in the movie where Joey (Katharine Houghton) tells the maid another person is coming to dinner, to which Tillie (Isabel Sanford), the maid guesses, "The Reverend Martin Luther King?" When King was murdered, the studio immediately called the theaters showing the film and gave instructions to cut that scene from the movie.
Mr Prentice (Roy Glenn) says to his son John (Sidney Poitier) "In 16 or 17 states you'll be breaking the law. You'll be criminals." By the time people saw the movie this was no longer true. On June 12th, 1967, the US Supreme Court in the case Loving v Virginia declared anti-miscegenation laws unconstitutional.
Due to Spencer Tracy's health, the cast was always working from two shooting scripts, one with Tracy, one without. Typically, Katharine Hepburn brought Tracy in the morning, they worked until she decided he was too tired, then Tracy and Hepburn left. Sidney Poitier, who already had received a Best Actor Oscar for Lilies of the Field (1963), was intimidated by working with two legends, and preferred to perform to empty high backed chairs.
This film was instrumental in largely ending the marketing consideration of how films featuring African-American characters and themes were assumed to be likely rejected by mainstream audiences in the Southern States of the USA. In that regard, the film was such a major widespread success throughout the entire USA, including the South, that the marketing factor would never again be considered a major problem for any major film release.
The three-inch bronze sculpture of Spencer Tracy featured in the film was created by Katharine Hepburn herself and was one of the items that were included in her estate auction in 2004. The bust was the most sought-after item and fetched the most money - it sold for $316,000, whereas pre-auction estimates were in the neighborhood of $3,000-$5,000.
Joey says to her father, "Even if you had any objections, I wouldn't let him go now, even if you were the governor of Alabama. I mean if Mom were." Joey makes that correction in reference to the fact that during the filming of this movie, the governor of Alabama was a woman, Lurleen Burns Wallace - the wife of the multi-term, notoriously segregationist Alabama Governor George Wallace.
The film debut of Isabel Sanford, who later gained fame as Louise on The Jeffersons (1975). In 1981, she became the first African American woman to win an Emmy Award for Outstanding Lead Actress in a Comedy Series. Ironically, D'Urville Martin (Frankie) appeared in the two All In The Family pilots as Lionel Jefferson.
Sidney Poitier, born February 20, 1927; was only 13 years younger than the actor portraying his father, Roy Glenn, born June 3, 1914, and only 7 years younger than the actress portraying his mother, Beah Richards, born July 12, 1920. However, Katharine Houghton, born March 10, 1945 was appropriately age spaced with the actors portraying her parents, Spencer Tracy, born April 5, 1900 (45 years older), and Katharine Hepburn, born May 12, 1907 (38 years older).
When Dr. John Prentice (Sidney Poitier) makes the first long distance call to his parents in Los Angeles, he asks the operator for time and charges. At the end of the call he leaves $2.20 on the desk to pay for it. Adjusted for inflation with U.S. CPI data, the same call in 2015 would cost $16.07.
John says to Matt that Joey "feels that all of our children will be president of the United States and they'll all have colorful administrations." In 1960, seven years before this movie was released, a black economics student named Barack Obama and a white anthropology student named Ann Dunham met, fell in love, and got married. Like the characters of John and Joey in this movie, Barack and Ann were an interracial couple who met at the University of Hawaii during an era when interracial relationships and marriages were still taboos or even illegal in many parts of the country. In 2008, the child that Barack and Ann Obama had together, Barack Obama, did indeed become President of the United States.
The trivia items below may give away important plot points.
When the movie was conceived and launched by producer-director Stanley Kramer, one of Hollywood's greatest liberal movie-makers, intermarriage between African Americans and Caucasians was still illegal in 14 states. Towards the end of production, the U.S. Supreme Court handed down its decision in Loving v. Virginia. The Loving decision was made on June 12, 1967, two days after the death of star Spencer Tracy, who had played a "phony" white liberal who grudgingly accepts his daughter's marriage to a black man. In Loving, the High Court unanimously ruled that anti-miscegenation marriage laws were unconstitutional. In his opinion, Chief Justice Earl Warren wrote, "Marriage is one of the 'basic civil rights of man,' fundamental to our very existence and survival. To deny this fundamental freedom on so unsupportable a basis as the racial classifications embodied in these statutes, classifications so directly subversive of the principle of equality at the heart of the Fourteenth Amendment, is surely to deprive all the State's citizens of liberty without due process of law. The Fourteenth Amendment requires that the freedom of choice to marry not be restricted by invidious racial discriminations. Under the American Constitution, the freedom to marry, or not marry, a person of another race resides with the individual and cannot be infringed by the State." Interestingly, Kramer kept in the line of the African American father played by Roy Glenn, who tells his son played by Sidney Poitier, "In 16 or 17 states you'll be breaking the law. You'll be criminals." This was probably because Kramer realized that, despite the change in the law, the couple would still be facing a great deal of prejudice requiring a stalwart love for their marriage to survive, which was the message Tracy's character gives in an eight-minute scene that is the climax of the movie. The scene summing up the theme of the movie was the last one the dying Tracy filmed for the movie, and it was the last time he would ever appear on film. It took a week to shoot the scene and at the end, he was given a standing ovation by the crew. He died a little over a fortnight after walking off of a sound-stage for the last time.