As County Council chairman for 11 years and then mayor for eight more, Stephen K. Yamashiro was among the most influential political leaders during one of the most critical periods in the history of the Big Island.

Yamashiro, a blunt-talking Honolulu transplant, played a key role in transforming the Hawaii island economy from one dependent on the sugar industry to another diversified with resorts, other forms of agriculture, astronomy and varied industries.

Yamashiro died of pneumonia Tuesday night at Hilo Medical Center. Friends said he had fought through several aneurysms and heart surgeries in recent years. He was 69.

Longtime Honolulu Advertiser reporter Hugh Clark called Yamashiro “probably … the most significant newsmaker on the Big Island” during the last three decades of the 20th century.

Yamashiro served on the  Council from 1976 to 1990, 11 of those years as chairman. During that time, he was the undisputed leader, pushing through several key West Hawaii resort projects.

After the death of Mayor Bernard Akana in 1990, Yamashiro resigned from the Council to run in a special election. Lorraine Inouye, his one-time ally and rival on the Council, beat him by 76 votes.

Yamashiro won a rematch against Inouye for the county’s top post two years later.

“As Hawaii County Council chairman and mayor, Mayor Yamashiro led our community through a very difficult transition period,” current Mayor Billy Kenoi said in a statement.

“As the last of the plantations closed in the 1990s, the Big Island was searching for new directions, and Mayor Yamashiro helped steer our island community into the future. His support and advocacy of sectors such as diversified agriculture, forestry and geothermal power are still paying dividends for our residents today. He knew where we needed to go, and he led the way. We are grateful for Mayor Yamashiro’s many contributions to our community.”

Yamashiro’s unabashed support for development projects and his no-nonsense nature on political issues often made him a polarizing figure, especially among those opposed to fast growth on the Kona side of the island.

Yet he had an ability to make friends with former enemies and, in private, displayed a sharp wit and dry humor.

State Agriculture Chairman Russell Kokubun served with Yamashiro on the Council, ran against him for mayor in 1992, then worked as his deputy planning director for several years.

Yamashiro was a strong proponent of developing the island, while Kokubun advocated more moderate growth, but that didn’t stop the two from becoming fast friends after the 1992 election.

“His wisdom and experience were unmatched,” Kokubun said Wednesday.

Even after leaving politics, Yamashiro continued to serve as a mentor for younger politicos and business people, Kokubun said.

Former Gov. Linda Lingle, a Republican, tapped Yamashiro, a lifelong Democratic Party stalwart, to serve on the Hawaii Tourism Authority for two consecutive four-year terms.

While the playbook called for them to be political adversaries, the two seemed to get along well while serving as mayors of neighboring counties. At Lingle’s invitation, Yamashiro’s wife, Della, once stayed in the governor’s mansion when Yamashiro was admitted to the Queen’s Medical Center.

In his political prime, Yamashiro was known for his often tough, no-nonsense style as a politician and his brusque nature turned off  some people.

“He was extremely bright, but also very strong-minded, or hard-headed, some might say,” Kokubun said. “But at least you knew where he was coming from.”

Reporter Clark said Yamashiro was never hesitant to get into policy battles.

“He was a maverick at times, a solid Democrat at others, but always was his own driver,” he said.

Yamashiro was astute at government finances, and Clark credited him with pushing forward the Kaumana bypass road and Mohouli street extension projects with the help of heavy federal funding.

Inouye, whom Yamashiro endorsed when she ran successfully for state Senate in 1998, said she “got a lot of my political smarts” learning from Yamashiro in the 1970s. Echoing Clark’s comments, Inouye called Yamashiro an expert on budget and government efficiency issues.

Inouye, a one-time hotel industry executive, said Yamashiro shared her vision of replacing jobs lost by the demise of the sugar industry with the development of resorts along what the late Gov. John A. Burns called the “Gold Coast” along North Kona and South Kohala.

“When it came to jobs and the economic situation, he made sure things got done and progressed,” Inouye said.

Born in Honolulu, Yamashiro graduated from Punahou School and the University of Hawaii at Manoa. He received his law degree from Willamette University in Oregon.

His first job with Hawaii County was as a deputy corporation counsel.

Among his survivors is his wife, Della.

Funeral arrangements are pending.