Dave Thomas, the smiling pitchman whose homespun TV ads built Wendy's Old-Fashioned Hamburgers into one of the world's most successful fast-food franchises, died Tuesday of liver cancer.

Thomas, who was 69, died at his home in Florida, the company said Tuesday.

Thomas had been undergoing dialysis for a kidney problem since early 2001. He also had quadruple heart bypass surgery in December 1996.

"He was the heart and soul of our company. He had a passion for great tasting hamburgers, and devoted his life to serving customers great food and helping those less fortunate in his community," said Jack Schuessler, chairman and chief executive of Wendy's, based in the Columbus suburb of Dublin.

The founder and senior chairman of Wendy's International became a household name when he began pitching his burgers and fries in television commercials in 1989. The smiling Thomas, always wearing a white short-sleeved shirt and red tie, touted the virtues of fast-food in humorous ads, sometimes featuring stars such as bluesman B.B. King and soap opera queen Susan Lucci.

"As long as it works, I'll continue to do the commercials," Thomas said in a 1991 interview. "When it's not working any longer, then I'm history."

Adoption Advocate

But burgers were not his first love. Thomas, who was adopted as an infant, became a national advocate for adoption.

He created the Dave Thomas Foundation for Adoption, a not-for-profit organization focused on raising public awareness of adoption. The profits from his books, Dave's Way and Well Done! go to the foundation.

He once testified before a congressional committee for a bill that would give a $5,000 tax credit to those who adopt children.

"I know firsthand how important it is for every child to have a home and loving family," he testified. "Without a family, I would not be where I am today."

Born July 2, 1932, Thomas was 12 when he got his first restaurant job -- as a counterman in Knoxville, Tenn.

In 1956, he was working at a barbecue restaurant in Fort Wayne, Ind., when Col. Harland Sanders of KFC fame stopped in on a promotional tour. Thomas's boss bought a KFC franchise, and six years later, Thomas came to Columbus to take over four failing Kentucky Fried Chicken restaurants.

He sold them back to the founder in 1968 for $1.5 million, making him a millionaire at 35.

He opened his first Wendy's Old Fashioned Hamburgers in Columbus a year later. He named the restaurant after his 8-year-old daughter Melinda Lou, nicknamed Wendy by her siblings.

The chain grew to 4,800 restaurants in the United States and 34 countries by 1996. That year, Wendy's acquired the 1,200-store, Canadian-based Tim Hortons chain of coffee and fresh-baked goods.

He tried to retire in 1982, but came back in 1989.

"They took the focus off the consumer," he said of the executives who took over the company.

In 1999 Thomas temporarily took charge of the company after the second death of its chief executive and president in less than four years. John Schuessler, formerly head of Wendy's U.S. operations, was appointed to those positions in 2000.

But it was the TV commercials that made Thomas famous. Industry analysts and company officials said the ads helped the company rebound from a difficult period in the mid-1980s when earnings sank.

"He's given Wendy's a corporate identity ... a down-homey type image. The lack of sophistication is a real benefit for the company," one financial analyst said in 1991.

In 1996, Thomas filmed his 500th commercial. The company staged a lookalike contest that attracted 1,600 entrants vying for the grand prize: a chance to appear in a commercial with Thomas.

Thomas, who told the story of his life in Dave's Way, told 2,500 Columbus public school seniors in 1993 -- the year he earned a high school equivalency certificate -- that his biggest mistake was not finishing high school.

"We have 4,000 restaurants today, but if I had gotten my high school diploma, we might have 8,000," he said.

Reuters and the Associated Press contributed to this report.