Rocky Aoki, the Tokyo-born restaurateur whose Benihana steakhouse restaurants brought a version of Japanese teppanyaki cooking to the U.S. long before the explosive popularity of sushi, has died. He was 69.

Aoki died last night, according to a company spokeswoman, Nancy Bauer. Kyodo news service, citing unidentified people, said he died in New York City.

No cause was given. Aoki said publicly on several occasions that he suffered from diabetes and cirrhosis of the liver, as well as hepatitis C, which he said he contracted from a blood transfusion.

With Aoki as chief executive and chairman, Miami-based Benihana Inc. grew to run or license about 90 restaurants worldwide. They serve up steak, chicken and shrimp dishes prepared tableside by chefs trained to be showmen as well as cooks.

Aoki resigned in 1998, staying on as a $500,000-a-year consultant, amid a federal investigation of his personal investments. In 1999, he pleaded guilty to insider trading, acknowledging that he profited from a tip that Spectrum Information Technologies Inc. was about to hire former Apple Computer Inc. chief John Sculley.

Aoki was sentenced to three years' probation and fined $500,000. He told the New York Times in 2000 that he was worth $30 million to $40 million and still couldn't figure out why he had broken the law to make less than a half-million-dollar profit.

"I'm a risk-taker to start with," he said. "I'm not a professional so-called investor. I kill myself for that. I don't know why I did it."

As a risk-taker, Aoki sponsored and competed in offshore powerboat racing and suffered serious injuries during races in 1979 and 1982. He said in 1983 that he was retiring from the sport because it had become too dangerous. He also crossed the Pacific Ocean in a hot-air balloon in the early 1980s, Kyodo reported.

His family life was something of a show as well. Thrice married, Aoki admitted that three of his seven children were conceived, by different women, in a single one-year span. A 2006 New York magazine article on the family's legal battle over money said he had long kept a mistress hidden from his first wife, Chizuru — and other girlfriends hidden from both of them.

Hiroaki Aoki was born Oct. 9, 1938, in Tokyo. He and his three younger brothers grew up around their parents' restaurant and learned "the importance of absolute cleanliness in the kitchen, using the freshest ingredients and the very best cooking tools money could buy,'' according to a company history on the restaurant chain's Web site.

Aoki earned a spot on the Japanese Olympic wrestling team and first traveled to the U.S. on an athletic scholarship. He adopted the name "Rocky'' and sold ice cream in New York City by day while studying restaurant management at night, according to the company history. He was mugged three times and stabbed twice during his ice-cream-selling days, the history goes.

In 1964, he opened his first Benihana of Tokyo restaurant — with four tables — on West 56th Street. He opened a second restaurant just three blocks to the east, then one in Chicago. By 1972, he was running six branches.

Benihaha shares fell 25 cents today to $5.96 as of 4 p.m. New York time in Nasdaq stock market composite trading. It has dropped 53 percent so far this year.