Coppola and Puzo originally wanted the title to be The Death of Michael Corleone but this was not acceptable to Paramount Pictures. Coppola states that The Godfather series is in fact two films, and Part III is the epilogue. Part III received mixed to positive reviews, grossed $136,766,062 and was nominated for seven Academy Awards.
At a ceremony in St. Patrick's Old Cathedral, Michael is named a Commander of the Order of St. Sebastian. At a party following the ceremony, Anthony tells his father that he is going to drop out of law school to pursue a career as an opera singer. Kay supports his choice, but Michael disagrees, wishing that his son would either finish law school or join the family business, but Anthony refuses to have anything to do with his father's "legacy". Michael and Kay have an uneasy reunion, in which Kay tells him that Anthony knows the truth about Fredo's death.
Meanwhile, Vincent Mancini (Andy Garcia), the illegitimate son of Michael's late brother Sonny, shows up at the party. He is embroiled in a feud with Zasa, who has involved the Corleone family in major drug trafficking and turned Little Italy into a slum. Michael's sister Connie (Talia Shire) arranges a "sit-down" between Vincent and Zasa in Michael's study. The discussion erupts into a fight, in which Vincent bites Zasa on the ear. That night Vincent has a one-night stand with a journalist named Grace Hamilton (Bridget Fonda). Two men armed with knives and a gun break in and try to kill him. Vincent kills them both, but not before learning that Zasa sent them. Michael is troubled by Vincent's fiery temper, but is nonetheless impressed by his loyalty, and agrees to take his nephew under his wing.
Meanwhile, Michael busies himself with the biggest deal of his career: He has recently bought up enough stock in International Immobiliare, an international real estateholding company known as "the world's biggest landlord", to become its largest single shareholder, with six seats on the company's 13-member board of directors. He now makes a tender offer to buy the Vatican's 25% interest in the company, which will give him controlling interest. Knowing that Archbishop Gilday (Donal Donnelly), who serves as head of the Vatican Bank, has run up a massive deficit, he negotiates a deal to pay $600 million to the Bank in exchange for the shares. The deal is quickly approved by Immobiliare's board. However, it must be ratified in Rome by Pope Paul VI, who is gravely ill. Without his word, the deal is in limbo.
Don Altobello (Eli Wallach), an elderly New York Mafia boss and old friend of the Corleones (as well as Connie's godfather), soon visits Michael, telling him that his old partners onthe Commission want in on the Immobiliare deal. Michael, however, is adamant that the deal shall be untainted by Mafia involvement. A meeting is arranged, and Michael appeases most of the Mafia bosses with payoffs from the sale of his Las Vegas holdings. Zasa, however, gets nothing and declares that Michael is his enemy and storms out. Altobello tells Michael that he will try to reason with Zasa and follows close behind. Minutes later, a helicopter hovers outside the conference room and sprays it with machine gun fire. Most of the other mob bosses are killed, but Michael, Vincent, and Michael's bodyguard, Al Neri (Richard Bright), escape. Back at his penthouse in New York, Vincent tells Michael that those mob bosses who escaped the massacre made deals with Zasa. Michael knows that Zasa was not the mastermind of the massacre due to Zasa's being "muscle" and not having the cunning to organize such a scheme. Vincent wants to kill Zasa, but Michael refuses. As he considers how to respond to the situation, he suffers a diabeticstroke and is hospitalized, but not before realizing Altobello is the traitor.
As Michael recuperates, Vincent begins a romantic relationship with Mary and plots revenge against Zasa. Neri and Connie give Vincent permission to act. During a street festival hosted by Zasa's Italian Americancivil rights group, Vincent's men gun down Zasa's bodyguards. Vincent, disguised as a policeman on horseback, shoots Zasa dead. When Michael discovers this, he berates Vincent for his rashness. Michael also insists that Vincent end his relationship with Mary, because Vincent's involvement in the family's criminal enterprises puts her life in jeopardy.
The family takes a vacation to Sicily in preparation for Anthony's operatic debut in Palermo at the Teatro Massimo. They stay at the villa of Corleone family friend Don Tommasino(Vittorio Duse). Michael tells Vincent to speak with Altobello and tell him that he is planning to leave the Corleone family. Altobello supports the idea of Vincent's switching his allegiance, and introduces him to Don Licio Lucchesi (Enzo Robutti), a powerful Italian political figure and Immobiliare's chairman. Michael realizes that the Immobiliare deal is an elaborate conspiracy among Lucchesi, Archbishop Gilday, and Vatican accountant Frederick Keinszig (Helmut Berger) to swindle him out of his money, and visits Cardinal Lamberto (Raf Vallone), the man favored to become the next Pope, to speak about the deal. Lamberto convinces Michael to make his first confession in 30 years, in which he tearfully admits to ordering Fredo's murder. Lamberto tells Michael that he deserves to suffer for his sins, but that his life could still be redeemed.
Shortly after the meeting between Vincent and Lucchesi, Altobello travels to the small village of Montelepre, where he hires Mosca (Mario Donatone), a veteran hitman, to assassinate Michael. A few days later, Mosca and his son, disguised as priests, attempt to kidnap Don Tommasino and force him to allow them entry to his villa. Tommasino refuses, and Mosca kills him. While touring Sicily with Kay, who has arrived for Anthony’s operatic debut, Michael asks for her forgiveness. As they both admit that they still love each other, Michael receives word that Tommasino is dead. At Tommassino's funeral, Michael swears over his old friend's coffin to sin no more.
After the death of Pope Paul VI, Cardinal Lamberto is electedPope John Paul I, which means that the Immobiliare deal will likely be ratified. The new Pope's intentions come as a death knell to the plot against the ratification of the Immobiliare deal, prompting frantic attempts by the plotters to cover their own tracks. Vincent tells Michael that he has learned from Altobello of Mosca's plot on his life. Michael sees that his nephew is a changed man, and makes him the new Don of the Corleone family. In exchange, Vincent agrees to put an end to his relationship with Mary.
The family travels to Palermo to see Anthony perform the lead in Pietro Mascagni's Cavalleria rusticana, a tale of murderous revenge in a Sicilian setting. Meanwhile, Vincent exacts his own revenge:
Keinszig is abducted by Vincent's men, who smother him with a pillow and hang him from a bridge to make his death look like a suicide.
Don Altobello, also attending the opera, eats poisoned cannoli that his goddaughter Connie gives him. He dies as Connie watches sadly from her box.
Finally, Calò (Tommasino's former bodyguard) meets with Don Lucchesi at his office, claiming to bear a message from Michael. As he pretends to whisper the message to Lucchesi, Calò stabs him in the throat with his own glasses.
The killings are too late to save the Pope, however. Just hours after he approves the Immobiliare deal, the Pope drinks poisoned tea provided to him by Archbishop Gilday and soon dies in his bed.
Mosca, still disguised as a priest and armed with a sniperrifle, descends upon the opera house during Anthony's performance, killing three of Vincent's men and preparing to shoot his target from a box, but the opera ends before he has the chance to pull the trigger. The assassin retreats to the opera house façade's staircase and tries to shoot Michael there. At the same moment, Mary confronts her father about the forced break-up with Vincent. Mosca fires twice, wounding Michael and accidentally killing Mary. Vincent then shoots him dead. As Kay and Connie weep, Michael cradles Mary's body in his arms and screams in agony.
The scene dissolves to a short montage of Michael's memories of all the women he has lost, composed of scenes with Mary, Kay, and his first wife, Apollonia.
The film ends with Michael, an old man, sitting in the garden of Don Tommasino's Sicilian villa. He slumps over in his chair, falls sideways to the ground, and dies alone, with only his dog present.
Coppola felt that the first two films had told the complete Corleone saga. In his audio commentary for Part II, he stated that only a dire financial situation caused by the failure ofOne From The Heart compelled him to take up Paramount's long-standing offer to make a third installment.
According to an article in Premiere, Coppola and Puzo requested six months to complete a first draft of the script with a release date of Easter 1991. Paramount agreed to give them six weeks for the script and, lacking a holiday movie, a release date of Christmas Day 1990.
Al Pacino, Diane Keaton, and Talia Shire reprise their roles from the first two films. According to Coppola's audio commentary on the film in The Godfather DVD Collection, Robert Duvall refused to take part unless he was paid a salary comparable to Pacino's. On an episode of Inside the Actors Studio,[when?] Duvall said he understood that Pacino was the star but felt insulted by the difference in their salaries, saying "if they paid Pacino twice what they paid me, that's fine, but not three or four times, which is what they did." When Duvall dropped out, Coppola rewrote the screenplay to portray Tom Hagen as having died before the story begins. Coppola created the character B. J. Harrison, played by George Hamilton, to replace the Hagen character in the story. The director further states that, to him, the movie feels incomplete "without [Robert] Duvall's participation." According to Coppola, had Duvall agreed to take part in the film, the Hagen character would have been heavily involved in running the Corleone charities.
The first draft of a script had been written by Dean Riesner in 1979, based on a story by Mario Puzo. This script centered around Michael Corleone's son, Anthony, a naval officer working for the CIA, and the Corleone family's involvement with a plot to assassinate a Central Americandictator. Almost none of the elements of this early script carried over to the final film, but one scene from the film — in which two men break into Vincent's house — exists in the Riesner draft and is nearly unchanged.
Coppola says that he felt The Godfather saga was essentially Michael's story, one about how "a good man becomes evil," as the writer/director puts it on the same commentary track referenced above. Coppola says he felt that Michael had not really "paid for his sins" committed in the second film, and wanted this final chapter to demonstrate that. In keeping with this theme, Coppola completely re-wrote the script.
Julia Roberts was originally cast as Mary, but dropped out due to scheduling conflicts.Madonna wanted to play the role, but Coppola felt she was too old for the part.Rebecca Schaeffer was set to audition, but she was murdered. Winona Ryder dropped out of the film at the last minute. Ultimately Sofia Coppola, the director's daughter, was given the role of Michael Corleone's daughter. Her much-criticized performance resulted in her father being accused of nepotism, a charge Coppola denies in the commentary track, asserting that, in his opinion, critics, "beginning with an article in Vanity Fair," were "using [my] daughter to attack me," something he finds ironic in light of the film's denouement when the Mary character pays the ultimate price for her father's sins.
As an infant, Sofia Coppola had played Michael Corleone's infant nephew in The Godfather, during the climacticbaptism/murder montage at the end of that film. (Sofia Coppola also appeared in The Godfather Part II, as a small immigrant child in the scene where the nine-year-old Vito Corleone arrives by steamer at Ellis Island.) The character of Michael's sister Connie is played by Francis Ford Coppola's sister, Talia Shire (making her both Mary and Sofia's aunt). Other Coppola relatives with cameos in the film included his mother, father (who wrote and conducted much of the music in the film), uncle and granddaughter, Gia. Michele Russo, who plays the son of the assassin Mosca, is also a distant Coppola relative, from the same town as Francis Ford Coppola's great-grandmother. In addition, Coppola cast Catherine Scorsese, mother of Martin Scorsese, in a small part.
At Rotten Tomatoes, the film received a mixed to positive response with a 68% "fresh" rating. At Metacritic, which assigns a normalized rating out of 100 to reviews from mainstream critics, the film received an average score of 60, based on 19 reviews, which indicates "mixed or average reviews".
The Godfather Part III is almost unanimously considered to be the weakest of the three Godfather films. Common criticisms include Sofia Coppola's acting, the plot being too outlandish and convoluted, and being too based on continuity, rather than just a "stand alone" story.
In his review, Roger Ebert stated that it is "not even possible to understand this film without knowing the first two." Nonetheless, Ebert wrote an enthusiastic review, awarding the film three-and-a-half stars, a better rating than he gave The Godfather Part II. He also defended the casting of Sofia Coppola, who he felt was not miscast, stating, "There is no way to predict what kind of performance Francis Ford Coppola might have obtained from Winona Ryder, the experienced and talented young actress, who was originally set to play this role. But I think Sofia Coppola brings a quality of her own to Mary Corleone. A certain up-front vulnerability and simplicity that I think are appropriate and right for the role."
Ebert's colleague, Gene Siskel, also highly praised the film and placed it on his list of the ten best films of 1990 (#10). Siskel admitted that the ending was the film's weakest part, citing Al Pacino's makeup as very poor.
Leonard Maltin gave the movie three out of four stars and stated in his movie guide that the film is "masterfully told", but the casting of Sofia Coppola was an "almost-fatal flaw".
Parts of the film are very loosely based on real historical events concerning the ending of the papacy of Paul VI, and the very short duration of John Paul I in 1978, and the collapse of the Banco Ambrosiano in 1982. Like the character Cardinal Lamberto, who becomes John Paul I, the historical John Paul I, Albino Luciani, reigned for only a very short time before being found dead in his bed.
Journalist David Yallop argues that Luciani was planning a reform of Vatican finances and that he died by poisoning; these claims are reflected in the film. Yallop also names as a suspect Archbishop Paul Marcinkus, who was the head of the Vatican bank, like the character Archbishop Gilday in the film. However, while Marcinkus was noted for his muscular physique and Chicago origins, Gilday is a mild Irishman. The character has also drawn comparisons to Cardinal Giuseppe Caprio, as he was in charge of the Vatican finances during the approximate period of which the movie was based.
The character of Frederick Keinszig, the Swiss banker who is murdered and left hanging under a bridge, mirrors the fate (and physical appearance) of Roberto Calvi, the Italian head of the Banco Ambrosiano who was found hanging under Blackfriars Bridge in London in 1982 (it was unclear whether it was a case of suicide or, as the Italian idiom has it, "being suicided". Courts in Italy have recently ruled the latter.)  The name "Keinszig" is taken from Manuela Kleinszig, the girlfriend of Flavio Carbone who was indicted as one of Roberto Calvi's murderers in 2005.
On the audio commentary of the DVD, Francis Ford Coppola states that the character of Don Licio Lucchesi would be very recognizable for Italian citizens. The thick-rimmed glasses, the official police bodyguard while Michael meets the Don in Sicily, and a single quote at the end of the movie are supposedly clues that Don Lucchesi is (at least partly) based on Giulio Andreotti.