Leo D. Sullivan, a pioneer in animation who won an Emmy and contributed to a large number of cartoons over the course of a 50-year career, passed away at the age of 82.

Please read on to learn the reason for his demise.

Cause of death for Leo D. Sullivan: How did Leo D. Sullivan pass away?
On March 25 at Kaiser Permanente West Los Angeles Medical Center, Sullivan passed away from heart failure.

Characters have come to life thanks to Sullivan’s abilities in animation, storyboarding, directing, and producing during the course of his career. His list of accomplishments includes work for companies including Hanna-Barbera, Warner Bros, and Spunbuggy Works as well as the animated series “Hey, Oh, Hey, It’s Fat Albert,” “The Incredible Hulk,” “My Little Pony,” and “Flash Gordon.” Sullivan was a part of the “Soul Train” opening animation team in 1971.

The native of Lockhart, Texas, moved to Los Angeles in 1952 and started working as an errand boy for “Looney Tunes” animator Bob Clampett. Sullivan co-founded Vignette Films, a company that created educational videos about historical Black people for American schoolchildren, in the 1960s with veteran Disney animator Floyd Norman.

Later, the two would launch AfroKids, a website and streaming platform intended to provide “a wonderful experience for the entire Black family.” Leo Sullivan Multimedia Corp., Sullivan’s new charity, was just founded.

Sullivan has received two awards from the Black Filmmakers Hall of Fame in Oakland, California, and both the San Francisco Cartoon Museum and the Los Angeles African American Museum have displayed his works of art. At the Art Institute of California-Orange County, he additionally taught digital animation and 2D animation for three years.

He is survived by his wife Ethelyn, daughter Tina Coleman, and son Leo D. Sullivan Jr.