Koch was found at his southern Indiana home of what the family believes to be complications from diabetes, Holiday World spokeswoman Paula Werne said Monday.

Werne said Koch had been diagnosed with Type 1 diabetes while he was in college and used an insulin pump.

Koch's wife, Lori, was in Louisville, Ky., attending a show with their children, and he was fine when they talked by phone about 8:30 p.m. But Werne said they found him dead when they arrived home after 10 p.m.

Koch spurred the growth of the family-owned park, which was known as Santa Claus Land when his father and grandfather opened it in 1946. Its water park was added in 1993, and several new roller coasters and other new attractions have been built since then.

The park about 35 miles east of Evansville set an attendance record in 2009 as it drew more than 1 million visitors for the fourth straight year.

"We will carry on that tradition. We have since 1946. This will not impede us," said Koch's mother, Pat Koch. "He would want us to do that. My husband would want us to do that. My father and my father-in-law and all the people that went before us (would want us to do that."

Lt. Gov. Becky Skillman called Koch "a true leader in Indiana business and tourism."

"Will invested countless hours and his entire family has sacrificed much for the one purpose of bringing enjoyment to Hoosiers of all ages," she said.

Werne said the park was open Monday and that it would continue to be owned and operated by his family.

"It's a sad situation," said visitor Tracy Steele. "I'm really glad they decide to keep the park open, where we can can enjoy him and remember him."

Koch grew up in the town of Santa Claus, where he was the valedictorian of Heritage Hills High School in 1979. He received a bachelor's degree in electrical engineering from the University of Notre Dame and a master's degree in computer science from the University of Southern California.

Koch was a familiar face to Hoosiers, appearing in countless television commercials for the theme park.

He and his wife have three children, Lauren, 22, Leah, 19, and William, 16. Funeral arrangements were pending on Monday.