Michael is the youngest son of Don Vito Corleone. He is the youngest brother of Sonny and Fredo, and the older brother of Connie.
The Godfather: Part I
Michael Corleone's ascension to the head of the Corleone crime family is portrayed in Puzo's novel and the first film.
Michael initially wants nothing to do with the "family business", and is enrolled at Dartmouth College in search of a more Americanized life. After the United States' entry into World War II, he enlists in the Marines against his father's wishes and fights in the Pacific Theatre. For his bravery, Michael is featured in Life magazine in 1944, having been awarded the Navy Cross. Michael is discharged as a Captain to recover from wounds in 1945. He later re-enters Dartmouth, where he meets his future wife, Kay Adams (Diane Keaton).
When his father is nearly assassinated in 1945, he volunteers to murder the man responsible, Virgil "The Turk" Sollozzo (Al Lettieri). He also proposes to kill Captain McCluskey (Sterling Hayden), a police captain who removed his father's bodyguards from the hospital, presumably to set up his father to be killed. Although it is normally a hard-and-fast rule in the Mafia that law enforcement officials are not to be harmed, Michael successfully convinces his older brother Sonny (James Caan) that since McCluskey is serving as Sollozzo's bodyguard, he has crossed into their world and is fair game.
After committing the murders, Michael flees to Sicily under the protection of Don Tommasino, a longtime friend of his father's, and stays in exile for two years. While in Sicily, he marries a young woman named Apollonia (Simonetta Stefanelli), but she is killed by a car bomb intended for Michael. Fabrizio, one of his bodyguards, was paid by a rival family to plant the bomb.
While in Sicily, he learns that Sonny had been murdered, and he returns to New York in 1950. There, he reluctantly becomes involved in his family's criminal enterprises, taking over for his deceased brother as operating head of the family under Vito's supervision. The family's consigliere, Tom Hagen (Robert Duvall), and one of the caporegimes, Peter Clemenza (Richard S. Castellano), are somewhat skeptical of his ability, but the other capo, Sal Tessio (Abe Vigoda), thinks somewhat more of him. He marries Kay a year later, promising to make the family legitimate within five years.
Michael tries to buy a casino from Moe Greene (Alex Rocco) the casino is partly owned "off the record" by the Corleone family. He intends to move his family to Nevada. After his father's death in 1955, he becomes official Don of the Corleone crime family. Before his death, Vito had warned Michael that after he was gone, the head of the rival Barzini family would make an attempt on his life under the pretense of organizing a meeting in order to make peace. After Tessio inadvertently reveals that he had conspired with Emilio Barzini (Richard Conte) against him, Michael arranges the murders of Barzini and Philip Tattaglia. In the film, he also kills the other two Mafia chiefs, Carmine Cuneo, and Victor Stracci. Also targeted are Greene, Tessio, Fabrizio and Carlo Rizzi (Gianni Russo), his brother-in-law, who plotted with Barzini to have Sonny killed. With this violent attack, Michael cements his reputation and returns the Corleone family to its position as the most powerful crime family in New York.
When his sister Connie (Talia Shire) finds out that Michael had Carlo killed while he stood godfather to their baby, she flies into a rage. Michael dismisses it as hysteria, and when pressed by Kay, denies any involvement in the murder. Just minutes later, however, he meets with his capos, and Clemenza greets him as "Don Michael." In the film, Clemenza greets Michael as "Don Corleone" and kisses his hand. Unknown to Michael, Kay is watching this meeting, and realizes that Connie was telling the truth after all and that her husband has become the new Don Corleone.
Parallel story: The Sicilian (novel only)
Michael appears as a secondary character in Puzo's The Sicilian. During his two-year exile in Sicily, Michael is eager to return home to his family in New York, but is told by Clemenza that his father wants him to escort Salvatore "Turi" Guiliano safely back to America with him. As he learns more about the reputation and exploits of the legendary Guiliano, Michael becomes extremely intrigued to meet him, but Giuliano dies before the meeting can take place.
The Godfather: Part II
By the time of The Godfather Part II, Michael has moved to shake off his family's Mafia roots. Frank Pentangeli, a longtime associate of his father's, has taken over the family's operations in New York.
His efforts at going legitimate prove unsuccessful, however, as his enemies keep him involved in the underworld. He begins to work out a deal with business partner and rival Hyman Roth (Lee Strasberg) over control of casino operations, but Roth manipulates Michael's brother Fredo (John Cazale) into unwittingly providing him with information used to arrange an attempt on Michael's life.
Michael and Roth travel to Cuba to forge a partnership with Fulgencio Batista's regime, allowing them to conduct their operations freely. In the midst of the revolution of 1959, Michael discovers that Fredo has betrayed him.
Back home, Kay reveals she has aborted their child because she does not want to bring another son of his into the world. Michael divorces Kay and severs ties with her.
Following the death of their mother, Michael orders Fredo's murder, an act he would regret for the rest of his life.
The Godfather: Part III
By the time of The Godfather Part III (the late 1970s) Michael has taken great steps to making the family legitimate; he is preparing to hand over his interests in gambling to the other Mafia families, setting up a charitable foundation, and is even being recognized by the Vatican for his good works. This new connection to the Church gives Michael the opportunity to purchase a controlling stake in the large property conglomerate, Immobiliare. He also begins to rekindle his relationship with Kay, as well as taking Sonny's illegitimate son, Vincent Mancini (Andy Garcia), under his wing. He finds himself pulled back into the underworld, however, when almost the entire Mafia Commission is wiped out by an assassin as Michael prepares to hand over his criminal interests. Vinnie responds to this new threat against the Family with brutal violence, publicly gunning down Michael's rival, Joey Zasa (Joe Mantegna), who was thought to have ordered the hit on Michael. Vinnie also begins a relationship with Michael's daughter, Mary (Sofia Coppola), a romance Michael strongly disapproves of.
At the end of the film, weary of the bloody, lonely life of a Don, he retires and makes his nephew the new head of the family, on condition that he end the relationship with Mary. Realizing that powerful interests in Italian politics and business were working to prevent the family's takeover of Immobiliare, Michael, with Vinnie's assistance, once again prepares to move against his enemies. This wave of murders takes place as Michael watches his son Anthony (Franc D'Ambrosio) perform in the opera Cavalleria Rusticana. That same night, however, Mary is inadvertently killed in an assassination attempt on Michael himself. Devastated by this loss, Michael withdraws from life and retires to Sicily, where he dies years later (1997) of a diabetic stroke, sitting alone in a lawn chair.