David Giuliani, an entrepreneurial engineer who co-invented the Sonicare toothbrush and helped forge landmark Washington state law to combat climate change, has died. He was 75.

Giuliani believed that markets — if properly structured — could prod businesses to move off fossil fuels driving global warming. In 2018, while diagnosed with lung cancer, he founded the Low Carbon Prosperity Institute, a think tank that developed information and policy, and worked to rally support among businesses and lawmakers for legislation to spur that transition.

Those efforts culminated last year, when he worked closely with state Sen. Reuven Carlyle, who introduced the bill that became the Climate Commitment Act, which is designed to drive down Washington’s greenhouse gas emissions to net zero by 2050.

“He was discreet, quiet, behind-the-scenes, and had a driving passion around climate action,” Carlyle said. “My name is on the legislation, but his fingerprint is on every word.”

Giuliani had a home on Mercer Island and one in Friday Harbor, which is where he spent his final days. He died Thursday.

Giuliani was born May 26, 1946, in San Francisco, and after obtaining a graduate degree in electrical engineering at Stanford University, went to work at Hewlett-Packard. He was a co-inventor of the Sonicare toothbrush, which was born out of his own struggles in the 1980s with periodontal disease.


In dealing with his own plaque, Giuliani became convinced that “regular toothbrushes just weren’t doing the job,” and that electric toothbrushes could be improved, according to a video history of his career that he recorded for his family.

In the late 1980s, Giuliani teamed up with two University of Washington professors, Dr. David Engel and Dr. Roy Martin, to develop a better electric toothbrush. An initial device did not prove practical, and was scrapped. Then, after a lot of prototypes and testing, the first Sonicare model was introduced in 1992.

“It’s a good example of inventing stuff that really does the job,” Giuliani said in the video recorded for his family.

Giuliani formed a company called GEMTech, later renamed as Optiva, to produce and market Sonicare, which fended off competitors in legal battles, according to Engel, who left the University of Washington to work with Giuliani.

“It was a real task to get it to where it ended up … one of the popular and effective power toothbrushes in the world,” Engel said.

Giuliani served as Optiva’s CEO until it was sold to Philips in 2002.


He also was a co-inventor of the Clarisonic skin care product, which was sold to L’Oreal in 2011.

While under Giuliani’s ownership, Sonicare and Clarisonic products were assembled at a building in Factoria, then moved to other locations in Washington, according to Bill McLain, who worked with Giuliani.

“The supply chain was short. He was able to introduce new products and make things happen quickly,” McLain said.

Guiliani was a ham radio enthusiast and loved to play classic rock on his guitar. But as he turned 65, he did not opt to retire to his hobbies and travel. Instead, Giuliani turned more to philanthropy with a focus on climate change. He backed research to develop blueprints for shifting away from fossil fuels, and supported efforts to educate legislators and the public on how to move forward as he co-founded the Washington Business Alliance, the Low Carbon Prosperity Institute and Clean & Prosperous Washington.

“He did not have to do any of this. But he took it as his job,” said Isaac Kastama, who started working with Giuliani in 2012 and was a lobbyist for Clean & Prosperous Washington.

Kastama said that Giuliani viewed reducing carbon emissions as a system-engineer problem but also as a political problem.


He and his late wife, Patricia Giuliani, contributed $160,000 to the unsuccessful Initiative 732 in 2016 that sought to pass a revenue-neutral Washington carbon tax. During the 2020 election cycle, he formed Clean and Prosperous America, which spent more than $1 million, with most of the money going to groups working on increasing the turnout of young voters, according to a statement from the group.

In the Washington Legislature, Giuliani was involved for years in efforts to develop a law that would put a price on carbon and other greenhouse gas emissions.

The Climate Commitment Act that passed in 2021 covers 100 large emitters in the state and about 75% of the overall annual greenhouse gas emissions. Emissions must be lowered over time. Some of these polluters will have to pay for the release of greenhouse emissions, generating revenue that can be invested in a range of activities, including helping low-income people adjust to the clean-energy transition.

During the past year, Giuliani stayed engaged in watchdogging the development of state regulations that will implement the new law. He was still engaged in that task even in his final weeks.

“Just days ago, my last conversation with him, he was just drilling me on how we are going to get to the next steps. He was passionate about his contribution to making the planet a better place,” said Michael Mann, executive director of Clean & Prosperous Washington. “His body was failing him, but his mind was not, at all.”

In a statement released last week, Gov. Jay Inslee said Giuliani was a remarkable leader, and “an inspiration to me.”

Giuliani, a nonsmoker, died of metastatic lung cancer.

He is survived by his children Nicole Giuliani and her husband, Jeb Weinstein; Dan Giuliani and his partner Regan Spencer; his sisters, Patrice Nicholas and Mary Ashuckian; and grandchildren; and his partner, Tracy Bryan.

The family asks that contributions in his memory be made to local food banks.