Steamboat Willie in the Public Domain: Testing the Boundaries of Copyright and Trademark Law

Copyright law has long grappled with the fate of Disney’s Steamboat Willie, the 1928 animated short film that featured the first iterations of Disney’s beloved Mickey Mouse and Minnie Mouse. Although the film’s copyright was originally set to expire decades ago, Disney’s persistent lobbying led to major legislative changes, including the Copyright Act of 1976 and the Sonny Bono Copyright Term Extension Act of 1998, often called the “Mickey Mouse Protection Act.”[1] These extensions pushed the copyright term to ninety-five years, delaying Steamboat Willie’s entry into the public domain until January 1, 2024.[2]

With Steamboat Willie now in the public domain, the original versions of Mickey and Minnie Mouse can now be used by anyone to create, adapt, or build upon these early character iterations without Disney’s permission.[3] However, this freedom is not absolute. While the public can use and make derivatives of the 1928 versions, later developments and copyrighted aspects of the characters remain protected, meaning new works based on the public domain material must avoid infringing on subsequent copyrighted versions.

On September 17, 2025, the law firm Morgan & Morgan filed a complaint against Disney Enterprises Inc., asserting that Disney continues to exert control over Steamboat Willie despite its entry into the public domain.[4] The firm alleges that Disney attempts to maintain intellectual property claims over elements from the 1928 cartoon, particularly the original depiction of Mickey Mouse, even after the expiration of the film’s copyright.[5]

According to the complaint, Morgan & Morgan produced an advertisement using visual elements from Steamboat Willie in reliance on its public domain status, and included clear disclaimers to avoid any implication of a connection to Disney.[6] However, when Morgan & Morgan sent the advertisement to Disney and informed it of the firm’s intention to air the commercial nationwide, Disney refused to affirmatively state that it would not sue Morgan & Morgan. Instead, it responded to Morgan & Morgan by stating that Disney continues to hold certain trademark rights over Steamboat Willie. The firm seeks a judgment declaring that Morgan & Morgan’s advertisement does not infringe upon any of Disney’s trademark or other intellectual property rights,[7] and invokes the Lanham Act, citing claims related to trademark infringement, false designation of origin and unfair competition, and trademark dilution.[8]

Morgan & Morgan further contends that Disney’s longstanding pattern of aggressive intellectual property enforcement, including recent lawsuits against third parties using Steamboat Willie imagery, creates a credible threat of litigation.[9] The complaint alleges that Disney’s refusal to disclaim any intent to sue over the advertisement, combined with ongoing trademark enforcement, has caused business harm and deterred the firm’s lawful use of public domain content.[10] Morgan & Morgan maintains that its advertisement does not infringe any valid trademark rights, does not constitute false designation of origin or unfair competition, and does not dilute any famous marks. The firm also seeks a declaration that its conduct does not violate any common law or statutory unfair competition laws.[11]

The court’s ruling in this case will be significant in clarifying the extent to which characters and elements from works that have entered the public domain can be freely used by others. The outcome will help define the boundaries between copyright expiration, ongoing trademark rights, and the public’s ability to use iconic characters once their original works are no longer protected by copyright law.

Cullen and Dykman’s Intellectual Property team continues to monitor important developments in trademark and copyright law. Should you have any questions about this legal alert, please feel free to contact Karen Levin (klevin@cullenllp.com) at (516) 296-9110, Ariel Ronneburger (aronneburger@cullenllp.com) at (516) 296-9182, or Jordan Milite (jmilite@cullenllp.com) at (516) 296-9128.

This advisory provides a brief overview of the most significant changes in the law and does not constitute legal advice. Nothing herein creates an attorney-client relationship between the sender and recipient.

Footnotes

[1] Kaitlyn Hennessey, Intellectual Property-Mickey Mouse's Intellectual Property Adventure: What Disney's War on Copyrights Has to Do with Trademarks and Patents, 42 W. New Eng. L. Rev. 25, 28 (2020).

[2] Id.

[3] § 13:19. Defenses Commonly Arising in Copyright Litigation—Public domain, Copyright Litigation Handbook § 13:19 (2d ed.) (citing Dastar Corp. v. Twentieth Century Fox Film Corp., 539 U.S. 23, 33 (2003)).

[4] Morgan Global, PLLC, v. Disney Enterprises, Inc., Case No. 6:25-cv-01795 (M.D. Fla. Sept. 17, 2025).

[5] See id. at ¶ 9.

[6] Id. at ¶¶ 20-22.

[7] See id. at ¶¶ 42-49.

[8] See id. at ¶¶ 31-41.

[9] Id. at ¶ 11.

[10] Id. at ¶ 10.

[11] See id. at ¶¶ 50-57.