Martin Sklar in 2005. (Jae C Hong/AP)

Martin A. Sklar, a right-hand man to Walt Disney and a central figure in the development and expansion of the Disney company’s theme parks around the world, died July 27 at his home in Hollywood Hills, Calif. He was 83.

Disneyland spokeswoman Suzi Brown confirmed the death but provided no other details.

Mr. Sklar had roles in the development of every Disney park, from the original Disneyland in Southern California in 1955 to the Shanghai Disney Resort last year. He was revered by employees as a living link to the founder.

Mr. Sklar condensed Walt Disney’s ideas into a widely circulated creed called “Mickey’s 10 Commandments,” which many considered key to the parks’ remarkable success and longevity. He spelled them out in a 2015 book, “One Little Spark!”

They included: Know your audience; organize the flow of people and ideas; avoid overload; and for every ounce of treatment, provide a ton of fun.

Mr. Sklar was still a college student at UCLA when he was hired to create the Disneyland News for the original park and became a full-time Disney employee the following year.

For the next 54 years, he led the development and expansion of the company’s parks. He was among the first to have the unique-to-Disney title of “imagineer” when he became the company’s chief creative leader for theme parks.

“Marty was one of Walt’s most trusted advisers and helped turn his most ambitious dreams into reality,” said Bob Weis, current president of Walt Disney Imagineering. “For us, it’s hard to imagine a world without Marty, because Marty is synonymous with Imagineering.”

Mr. Sklar scripted speeches for Walt Disney along with design and marketing materials for the parks and a film showing Disney’s vision for Walt Disney World and Epcot in Florida before they were built.

He had a hand in the design of memorable Magic Kingdom attractions such as the “The Enchanted Tiki Room,” “It’s a Small World” and “Space Mountain.”

Like most Disney designers, Mr. Sklar had to face criticism from hardcore fans. He felt the need to respond to complaints when “It’s a Small World” added characters from Disney films to its usual cast of international children.

“We are not trying to turn this classic attraction into a marketing pitch for Disney plush toys,” Mr. Sklar said at the time. “We are not ‘young marketing whizzes’ trying to make a name for ourselves.”

When the company made over Disneyland’s Tomorrowland in 1998, he explained the company’s constant intent to forge forward. “The future is a moving target, and you have to keep aiming at it,” he said.

Mr. Sklar retired in 2009, but he was still a frequent presence and ambassador at Disney events, including the company’s D23 Expo earlier this month.

Survivors include his wife of 60 years Leah, and a son, Howard Sklar.

At Disneyland’s 50th anniversary in 2005, Mr. Sklar summed up his life’s work as he walked into the park.

“I think Disneyland is so much about reassuring people the world can be okay, that things can be orderly, that you can speak to a stranger,” he told the Associated Press. “All those things that we are losing or have lost in our daily lives.”

— Associated Press