quality:correction, information:extraction, linguistic:paraphrasing, stylistic:style_transfer, quality:corruption
1974–1980: Scorsese collaboration and acclaim

De Niro had a pivotal role in Francis Ford Coppola 's crime epic The Godfather Part II (1974), playing the young Vito Corleone. De Niro had previously auditioned for the first installment, The Godfather (1972), but quit the project in favor of doing The Gang That Couldn't Shoot Straight. Coppola, having remembered him, gave De Niro a role in Part II instead. To portray his character, De Niro spoke mainly in several Sicilian dialects, although he delivered a few lines in English. The film was a commercial success and grossed $48 million at the worldwide box office. The Godfather Part II received eleven nominations at the 47th Academy Awards, winning six, including one for De Niro as Best Supporting Actor. It was De Niro's first Academy win; Coppola accepted the award on his behalf as he did not attend the ceremony. De Niro and Marlon Brando, who played the older Vito Corleone in the first film, were the first pair of actors to win Academy Awards for portraying the same fictional character.

After working with Scorsese in Mean Streets, De Niro collaborated with him again for the psychological drama Taxi Driver (1976). Set in gritty and morally bankrupt New York City following the Vietnam War, the film tells the story of Travis Bickle, a lonely taxi driver who descends into insanity. In preparation for the role, De Niro spent time with members of a U.S. army base to learn their Midwestern accent and mannerisms. He also lost 30 pounds (13 kg) in weight, took firearm training and studied the behavior of taxi drivers. The film was critically acclaimed, in particular for De Niro's performance; The Washington Post critic hailed it as his "landmark performance", and the San Francisco Chronicle wrote "De Niro is dazzling in one of his signature roles". The film was nominated for four Academy Awards, including Best Actor for De Niro. His " You talkin' to me? " quote, which he improvised, was selected as the 10th most memorable quote in the AFI's 100 Years...100 Movie Quotes by the American Film Institute. In 2005, the film was chosen by Time magazine as one of the 100 best films of all time.

De Niro had two other film releases in 1976. He starred in 1900, a historical drama directed by Bernardo Bertolucci. Starring an ensemble cast, the film is set in the Emilia region of Italy, and tells the story of two men, the landowner Alfredo Berlinghieri (De Niro) and the peasant Olmo Dalcò (Gérard Depardieu), as they witness and participate in the political conflicts between fascism and communism in the first half of the twentieth century. Next, he played a CEO in The Last Tycoon, based on F. Scott Fitzgerald 's novel of the same name, as adapted by British screenwriter Harold Pinter. De Niro lost 42 pounds (19 kg) for the role, and director Elia Kazan observed that De Niro would rehearse on Sundays, adding "Bobby and I would go over the scenes to be shot. Bobby is more meticulous... he's very imaginative. He's very precise. He figures everything out both inside and outside. He has good emotion. He's a character actor: everything he does he calculates. In a good way, but he calculates". The film received mixed reviews; Variety magazine ' s critic opined that the film was "unfocused" and called De Niro's performance "mildly intriguing". Film critic Marie Brenner wrote, "it is a role that surpasses even his brilliant and daring portrayal of Vito Corleone in The Godfather Part II... his performance deserves to be compared with the very finest".

For De Niro's sole project of 1977, he starred in Scorsese's musical drama New York, New York opposite Liza Minnelli. De Niro learned to play the saxophone from musician Georgie Auld, to portray saxophonist Jimmy, who falls in love with a pop singer (Minnelli). The film received generally mixed reception, although critics were kinder to De Niro. The film was nominated for four Golden Globe awards including Best Actor in a Motion Picture Musical or Comedy for De Niro. In 1978, De Niro starred in Michael Cimino 's epic war film The Deer Hunter, in which he played a steelworker whose life was changed after serving in the Vietnam War. He co-starred with Christopher Walken, John Savage, John Cazale, Meryl Streep, and George Dzundza. The story takes place in Clairton, Pennsylvania, a working-class town on the Monongahela River south of Pittsburgh, and in Vietnam. Producer Michael Deeley pursued De Niro for the role, because the fame of his previous films would help make a "gruesome-sounding storyline and a barely known director" marketable. De Niro, impressed by the script and director's preparation, was among the first to sign on to the film. Reviews for The Deer Hunter were generally positive, and the cast attracted strong praise for their performances. The film received nominations at the Academy Awards, Golden Globes and British Academy Film Awards (BAFTAs), and earned De Niro a nomination for Best Actor at the Academy Awards. In 2007, the American Film Institute ranked it as the 53rd-greatest American film of all time in their 10th Anniversary Edition of the AFI's 100 Years...100 Movies list.

The fourth collaboration between De Niro and Scorsese was in 1980, with the biographical drama Raging Bull. Adapted from Jake LaMotta 's memoir Raging Bull: My Story, De Niro portrays LaMotta, the Italian-American middleweight boxer whose violent behavior and temper destroyed his relationship with his wife and family. Co-starring Joe Pesci and Cathy Moriarty, De Niro later said it was one of the toughest roles to prepare for because he had to gain 60 pounds (27 kg), and had to learn to box. "The book's not great literature, but it's got a lot of heart", De Niro told Scorsese at the time. Although the film received critical acclaim, some reviewers were divided and criticized its "exceedingly violent" content; however, De Niro garnered praise for his realistic portrayal. The critic from The Hollywood Reporter declared that "De Niro is incredible and makes the actor almost unrecognizable as himself; he looks amazingly like La Motta. De Niro's appearance is also astonishing in the final scenes". Michael Thomson of the BBC observed "the power of Scorsese is matched by the intensity of De Niro who delves deep into the soul of the boxer". At the 53rd Academy Awards, the film received eight nominations, including Best Actor for De Niro for which he won. Raging Bull has since been regarded as one of the greatest films of the 1980s by American critics. De Niro was strongly considered for the role of Jack Torrance in Stanley Kubrick's The Shining, but it ended up going to Jack Nicholson, the director's first choice for the role.