It was the animation that launched the House of Mouse.
Steamboat Willie, a 1928 short film featuring the first non-speaking versions of Mickey and Minnie, is widely considered the moment that transformed Disney's fortunes and made cinematic history.
Their images are now publicly available in the United States, after Disney's copyrights expired.
This means that creatives and designers alike can now rework and use early versions of Mickey and Minnie.
In fact, anyone can use these versions without permission or fees.
But Disney has warned that more modern versions of Mickey are still covered by copyright.
“We will of course continue to protect our rights to more modern versions of Mickey Mouse and other works that remain subject to copyright,” the company said.
U.S. copyright law states that rights to the characters can be held for 95 years, meaning the Steamboat Willie characters entered the public domain on Monday, January 1, 2024.
These works can now be legally shared, performed, repurposed, repurposed, or sampled.
Early versions of Mickey and Minnie are just two of the works entering the public domain in the United States on New Year's Day.
Other films, books, music and famous people from 1928 are now also available to American audiences.
They include Charlie Chaplin's silent romantic comedy The Circus; English author AA Milne's book, The House at Pooh Corner, which introduces the character Tigger; Orlando by Virginia Woolf; and Lady Chatterley's Lover by DH Lawrence.
The UK has its own copyright rules and different expiration dates. For example, Lawrence's works are still protected by copyright until at least 2039.
Disney has repeatedly faced losing copyright to its original cartoons.
The characters were first scheduled to enter the public domain in 1984, but Congress extended the term by 20 years.
Before the next expiration date, in 2004, another 20-year extension was granted.
Disney's efforts to protect its characters even led to the law being nicknamed “the Mickey Mouse Protection Act.” But the time has finally come.
Jennifer Jenkins, director of the Duke Center for the Study of the Public Domain, told the BBC it was a “deeply symbolic and long overdue” step.
“What this means for us is that from 2024, anyone will be free to copy, share and expand on these original 1928 drawings and the characters they contain,” she said .
Jenkins said the moment was particularly significant because of Disney's “perceived role” in extending copyright terms, which kept its properties from entering the public domain for so long.
Disney still separately owns a trademark on Mickey as a brand identifier and corporate mascot. That means there are still limits to how the public can use these images, Jenkins said.
“What I can't do is start making merchandise and the same types of products that Disney sells,” she said.
“So if I'm selling T-shirts with Mickey and Minnie on them, and someone who sees those T-shirts mistakenly thinks they're buying a Disney product when they're not, that's that's where the mark ends.”
So any use of Mickey Mouse that gives the impression that he belongs to a brand other than Disney would still be a trademark issue.
Jack Kendall, a 32-year-old digital content creator from Warwickshire who runs a YouTube channel for Disney News Explainers, thinks someone might try to give Mickey and Minnie the horror movie treatment .
He compared this to when Winnie the Pooh entered the public domain and was made into the R-rated horror film, Blood and Honey, which was one of the lowest rated films of this year.
Kendall, who has more than 168,000 subscribers to his DSNY Newscast channel, believes Disney would want to avoid any further legal battles given that the company has become “a political lightning rod in pop culture.”
“But they also want to protect their two most identifiable characters,” he told the BBC.
He believes that Disney's active use of the trademarked versions in Steamboat Willie products, new animated shorts and even the studios' theatrical logo, is “Disney's way of protecting the characters if they want to go down the path legal in any blatant use of the characters.
A Disney spokesperson said that since Mickey Mouse first appeared in 1928, people have associated the character with the company.
“This will not change when the copyright on the Steamboat Willie film expires,” they said.
“More modern versions of Mickey will not be affected by the expiration of the Steamboat Willie copyright, and Mickey will continue to play a leading role as a global ambassador for the Walt Disney Company in our storytelling, attractions theme parks and our derivative products.”
The company added that it would “work to guard against consumer confusion caused by unauthorized uses of Mickey and our other iconic characters.”
Additional reporting by Leisha Chi-Santorelli