Peter Cullen’s Cause of Death Revealed a Week After His Passing

Optimus Prime’s powerful and principled voice has defined the childhoods of countless fans, first through Saturday morning cartoons and later in blockbuster films. Few voice actors have made such a lasting impact on a single character as the man behind that legendary Autobot leader.

Peter Cullen passed away on August 26 at his home in the Toluca Lake neighborhood of Los Angeles at the age of 85. His agent, Kevin Motley, confirmed the news, and Cullen’s family described his passing as peaceful, surrounded by loved ones, while fans mourned the loss of a voice that shaped much of their favorite childhood entertainment.

Now, about a week after his death was announced, the cause has been disclosed. According to a death certificate obtained by TMZ, Cullen died of cardiac arrest caused by respiratory arrest, with a malignant neoplasm of the lower lobe of the lungs listed as the underlying cause.

The official documentation also revealed several additional health complications that contributed to Cullen’s decline. Court records cited by PEOPLE noted secondary conditions including cerebellar metastasis, indicating that the cancer had spread to the cerebellum, along with hypoxia, chronic obstructive pulmonary disease, hypertension, and hyperlipidemia.

This combination of conditions suggests a prolonged and serious health struggle leading up to Cullen’s death, even as his family kept those details private during his final months. Cullen is set to be buried at Forest Lawn on September 9, allowing fans and colleagues to formally honor his legacy.

In their original statement following his passing, Cullen’s family reflected on how they wished him to be remembered. “Peter Cullen passed away peacefully, surrounded by his loving family, and held in the hearts of his many friends and countless fans worldwide,” the family stated, according to TMZ. They requested that fans “honor his remarkable legacy by serving your communities and leading others with compassion, integrity, and loyalty and always remember ‘be strong enough to be gentle.’”

Cullen first voiced Optimus Prime in the original 1980s ‘Transformers’ animated series, establishing a commanding yet compassionate tone that became synonymous with the character. He reprised the role across Michael Bay’s live-action film franchise, along with numerous animated series and video games over more than four decades.

His work extended beyond the ‘Transformers’ universe as well. Cullen was also beloved for voicing the gloomy donkey Eeyore in various ‘Winnie the Pooh’ projects, voicing Monterey Jack in ‘Chip ‘n Dale: Rescue Rangers,’ and providing the guttural vocal effects for the alien hunter in 1987’s ‘Predator.’

In a fitting final chapter, Hasbro confirmed that Cullen had recorded one last performance as Optimus Prime before his passing, for a short titled ‘Optimus Prime: Awakening,’ which will accompany the 40th-anniversary theatrical re-release of ‘The Transformers: The Movie.’ Frank Welker, who returns as Megatron and Soundwave opposite Cullen’s final performance, reflected on their decades-long collaboration, stating that Cullen’s portrayal of Prime was rooted in his personal values of honesty and loyalty, making their friendship an easy one.

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