He later served in the Oregon House of Representatives before appointment to the United States Senate in 1860 after the death of Edward D. Baker.

[1] In 1845, he sailed to what became Portland, Oregon, as the supercargo (cargo supervisor) of the Toulon,[2] bringing goods for Francis Pettygrove's warehouse.

[3][4] Stark bought the land for speculation rather than as a home or commercial property, and so he continued sailing as a merchant and visited the claim only occasionally.

[1][2] Around the time Stark left San Francisco in 1850 to set up shop in Portland,[1] he discovered his claim was disputed.

[7] In return for giving up the rest of the claim, Lownsdale, Coffin, and Chapman paid Stark for land they had already sold on his acreage, which was roughly 48 acres (190,000 m2) and included most of what was then downtown.

[10] Oregon's junior Senator, Edward Dickinson Baker, was killed in action during the American Civil War in October 1861.

[11] Oregon Governor John Whiteaker appointed Stark to replace Baker in the United States Senate and served from October 29, 1861, to September 12, 1862.

[2] He did not run in the election for a permanent replacement and was succeeded by Benjamin F. Harding, who had been Speaker of the Oregon House during Stark's time there in 1860.