In 1855, he volunteered to serve in the Indian War then taking place in Washington Territory. He served in several political offices. He was a county commissioner first for Thurston County (in what was then still part of the Oregon Territory), and then, after Washington became a separate territory, for King County, where Seattle is located. He also served as Seattle's first postmaster and in the territorial House of Representatives for nine consecutive terms, including serving a term as speaker. From 1861 to 1865 he was registrar of the General Land Office. He served as territorial delegate to the thirty-ninth United States Congress. Denny soon turned from politics to business. He returned to being a partner with Horton and Phillips, this time by taking a half interest in Dexter Horton and Co., the bank founded by Horton and Phillips in 1870, which would eventually become Seattle-First National Bank. He was president of the Seattle and Walla Walla Railroad Company and an investor in the Great Western Iron and Steel Company. Later in life, he was active in the Society of Washington Pioneers and wrote a memoir, Pioneer Days in Puget Sound. Among his other achievements, he was involved in founding the University of Washington and donated much of the land for its original site. On the current U.W. campus, Denny Hall, the former administration building (built 1895) is named in his honor. In 1962, he was inducted into the Hall of Great Westerners of the National Cowboy & Western Heritage Museum. Personality and politics Denny was an ascetic, a devout Christian (conservative in his religion to the point of opposing a divorce law), and a lifelong teetotaler. Indeed, he was teetotal to the point where he had the customers of his store buy their liquor direct from visiting ship captains so that he would not be involved in the transactions. He was a political conservative, and a cautious and conservative businessman and investor. Denny, in his memoir, described his decision to head north from Portland to Puget Sound as a "desperate venture". Lorraine McConaghy, historian at Seattle's Museum of History and Industry, agrees, but characterizes it further as "the only one he ever undertook." Women's suffrage Denny supported the right of women to vote, going so far as to introduce legislation in 1854 to allow white women of 18 years and older the right to vote. The resolution was voted