Davidson is an actively licensed certified public accountant. He was elected to four terms as Treasurer of Benton County, Washington. He took that office following his initial election in 2003. During Davidson's tenure as Benton County Treasurer, available public documents show that total outstanding year-end debt dropped from $24.4 million as of December 31, 2012 to $12.6 million as of December 31, 2016. Immediately prior to being elected as Benton County Treasurer, Duane was the Chief Financial Accountant for the county. Earlier in his career, as auditor for the Washington State Auditor’s Office, he served as the Assistant Audit Manager in the Tri-Cities in charge of the Walla Walla regional offices.
Davidson was elected state treasurer by winning 58% of the statewide vote against another Republican. Davidson has said his agenda as State Treasurer includes emphasizing financial education for consumers, and particularly students. In a May, 2017 visit to the Yakima, Wash. area, he visited a Junior Achievement program focusing on financial education and emphasized the utility of successful learning models already in use, rather than the development of new curricula by state agencies. Davidson has raised concerns about Washington state's total outstanding debt, and annual debt service costs. The state’s total outstanding obligations at the close of FY 2019 totaled $21.3 billion. He issues an annual report electronically by the request of the Legislature to each legislative member to provide an overview on the state's debt portfolio.
Personal life
He and his wife Kathy, raised three children together – daughters Bailey and Grace, and son Luke – in the Tri-Cities. While a county treasurer, Davidson served three terms as President of the Washington State Association of County Treasurers and earlier served as the organization’s treasurer. Davidson is a long-time Kiwanian. He is the past-president for two separate Kiwanis Clubs in the Tri-Cities and served as treasurer for the Kiwanis Club of Tri-Cities Industry Foundation. Davidson's youngest daughter, Grace, was his campaign manager for his 2016 election to state office. When his wife Kathy died in 2016, he contemplated dropping out of the race. Grace offered to be his campaign manager. She was 17 at the time. Duane has been vocal about the experience of having Grace run his campaign. Grace lead the Davidson campaign to victory and set multiple state records.
