Mr. Beatty’s career spanned more than four decades and more than 150 roles in movies such as “Superman,” “All the President’s Men,” “Rudy” and “Back to School.”Ned Beatty, who during a prolific acting career that spanned more than four decades earned an Oscar nomination for his role in “Network” and gave a cringe-inducing performance as a weekend outdoorsman assaulted by backwoods brutes in “Deliverance,” died on Sunday at his home in Los Angeles. He was 83.His death was confirmed by Deborah Miller, Mr. Beatty’s manager, who did not immediately provide details on the cause. Complete information on his survivors was not immediately available.Mr. Beatty appeared in more than 150 movies and television projects over the course of his career, frequently cast in supporting roles. While the beefy actor was not known as a leading man of the screen, he became associated with some of Hollywood’s most enduring films.His credits include “All the President’s Men” (1976), “Superman” (1978), “Rudy” (1993) and “Back to School” (1986).On television, Mr. Beatty played Stanley Bolander, the detective known as “Big Man,” on “Homicide: Life on the Street,” appearing on the television series from 1993 to 1995. He also played Ed Conner, the father of John Goodman’s character Dan Conner, on “Roseanne.”In 1976, Mr. Beatty was cast by Sidney Lumet and Paddy Chayefsky in “Network,” the critically acclaimed satire about a television network’s struggling ratings and a tube-obsessed nation. His character, Arthur Jensen, gave a memorable monologue in the movie, earning Mr. Beatty an Academy Award nomination for best supporting actor.In the scene, Mr. Beatty, playing the mustachioed network boss, summons the character Howard Beale, the anchorman played by Peter Finch, into the corporate boardroom and draws the curtains. With the camera trained on Mr. Beatty, who was standing at the opposite end of a conference table lined with banker lamps, he unleashed a ferocious soliloquy. Mr. Beale had a lot to learn about the ways of the corporate world, Mr. Beatty’s character sermonized.“And you have meddled with the primeval forces of nature, Mr. Beale,” Mr. Beatty said, his voice roaring. “And you will atone.”Mr. Beatty then modulated his delivery.“Am I getting through to you?” he said in a normal speaking voice.In “Mad as Hell: The Making of ‘Network’ and the Fateful Vision of the Angriest Man in Movies,” a 2014 book written by Dave Itzkoff, a culture reporter for The New York Times, Mr. Beatty said that he had been intimidated by the length of the speech, but excited by the character and the film.To get the filmmakers to commit to giving him the role, Mr. Beatty said, he told them that he had another movie offer for more money.“I was lying like a snake,” Mr. Beatty said. “I think they liked the fact that I was at least trying to be sly. I was doing something that maybe might be in their lexicon.”Mr. Beatty made his film debut in “Deliverance,” the 1972 big screen adaptation of James Dickey’s novel about four friends whose canoeing trip in rural Georgia turns calamitous. Stripped down to white underpants, his character, Bobby, is forced to “squeal like a pig” by a hillbilly before he is raped.The line would go down in movie infamy.“‘Squeal like a pig.’ How many times has that been shouted, said or whispered to me, since then?” Mr. Beatty wrote in a 1989 opinion piece for The New York Times.Mr. Beatty did not distance himself from the scene.“I suppose when someone (invariably a man) shouts this at me I am supposed to duck my head and look embarrassed at being recognized as the actor who suffered this ignominy,” he wrote. “But I feel only pride about being a part of this story, which the director John Boorman turned into a film classic. I think Bill McKinney (who portrayed the attacker) and I played the ‘rape’ scene about as well as it could be played.”Ned Beatty and Jon Voight in “Deliverance” (1972), in which Mr. Beatty made his feature film debut.Warner Bros., via PhotofestBorn on July 6, 1937, in Louisville, Ky., Mr. Beatty spent much of the early part of his acting career in regional theater, including eight years at the Arena Stage in Washington. In a 2003 interview, he told The Times that he averaged 13 to 15 shows per year onstage at the start of his career and spent as many as 300 days performing.In 2003, Mr. Beatty starred as Big Daddy in the Broadway revival of Tennessee Williams’s “Cat on a Hot Tin Roof,” appearing with Jason Patric and Ashley Judd. He was reprising his performance in the role of the Southern plantation owner, for which he had been nominated for an Olivier Award as part of the revival’s original London production.Candidly assessing his co-stars, Mr. Beatty said that Broadway had come to rely too heavily on celebrities, thrusting them into challenging roles they did not have the acting chops to handle.“In theater you want to go from here to there, you want it to be about something,” Mr. Beatty said. “Stage actors learn how to do that. Film actors often don’t even think about it. They do what the director wants them to do, and they never inform their performance with — call it what you wish — through-line, objective.”In “Superman” in 1978, Mr. Beatty played Otis, the bumbling toady of the villain Lex Luthor (Gene Hackman), a role that he reprised in “Superman II” in 1980.In 1986, he was cast in a comedic role as the gushing and unscrupulous Dean Martin of the fictional Grand Lakes University in “Back to School,” offering admission to Thornton Melon, the big and tall clothing tycoon (Rodney Dangerfield), in exchange for donating a building. The head of the business school in the film objected to the quid pro quo.“But I’d just like to say, in all fairness to Mr. Melon here, it was a really big check,” Mr. Beatty’s character retorted.Mr. Beatty delivered another memorable performance in a small role as Daniel Ruettiger, the blue-collar father in “Rudy,” the 1993 movie about a University of Notre Dame walk-on football player who makes the team. As the father enters the stadium for the first time, he is overcome by the moment.“This is the most beautiful sight these eyes have ever seen,” Mr. Beatty said. More