Christopher Reeve didn't enjoy working with Marlon Brando in Superman. In 1978, Richard Donner released what would remain to be the gold standard when it comes to adapting the Man of Steel on the big screen. Despite casting a relatively unknown actor in the titular role, the director pooled a few Hollywood A-listers for the supporting characters, like Gene Hackman, Ned Beatty, and Brando.
In Superman, Brando played Jor-El, Superman's biological father on Krypton who sent his child to Earth to save him from his planet's destruction. The actor didn't have much screen time in the movie, as he died at the very beginning. However, he continued to be a presence in it through the Fortress of Solitude; his recorded messages for Kal-El helped his son slowly become the ideal superhero. By the time he starred in the DC movie, Brando had already built an impressive acting portfolio, including playing Don Vito Corleone in Francis Ford Coppola's The Godfather, which released just six years prior. Despite this, Reeve wasn't exactly impressed with his seasoned co-star; in fact, he even went on to say that he didn't enjoy working with him on Superman.
In an old interview with David Letterman (via Twitter), the actor candidly revealed his thoughts when asked about his experience working alongside Brando in Superman. Reeve boldly said that he didn't "worship at the altar of Marlon Brando" because he felt like he copped out. He further explained his disappointment, saying that Brando could very well be an inspiration to a new generation of actors, but because the press continued praise him despite clearly no longer having passion for what he's doing, he can phone it in without any repercussions. It's bold of Reeve to call out Brando on national television, that even Letterman was quite surprised. However, as he said in the interview, his intention was not to spite Brando or cause any controversy. He was simply disappointed that one of the most talented actors in the industry seemed to not care about his craft anymore.
Brando initially garnered acclaim through Stanley Kubrick's 1951 film, A Streetcar Named Desire. His career continued with hits like On the Waterfront, The Wild One, Julius Ceasar, Viva Zapata!, and Sayonara. The '60s and early '70s, however, were difficult times for the actor; he had a series of flops and it didn't help that he was reportedly becoming difficult to work with. Couple that with some personal setbacks, and Brando started accepting roles for the sake of money - something that he himself admitted. Things turned out fine when The Godfather came out in 1972, followed by Bernardo Bertolucci's Last Tango in Paris, which was controversial but ultimately a hit. However, while Brando's performance was lauded, he confessed that he had a difficult time playing the lead role, Paul, in the erotic drama. Known for his method acting, Brando particularly struggled with the project due to the film's sensitivity that forced him to do some difficult scenes. Years later, he confessed that working took an emotional toll on him. Shortly after, personal tragedy struck when he lost his childhood best friend, which further stressed him out.
When Brando re-emerged for The Missouri Breaks in 1976, the reviews weren't kind on him. He was criticized for his uninspired performance as well as his declining physical state. By the time he filmed Superman, Brando practically threw caution out to the wind - as if he didn't care what the public thought of him anymore. He demanded a large sum of money despite having a relatively small, but important role. He refused to read the script beforehand, with his lines displayed off-camera during filming. Essentially, he was only willing to do the bare minimum. This was most likely what turned off Reeve during his experience working with the veteran actor in the Donner project.