[12] During the 2008 campaign, O'Brien left Stokes Lawrence to be a full-time volunteer for the Sierra Club and was encouraged to run for office by McGinn and others in the environmental community.

[13] In February 2009, O'Brien announced his candidacy for a city council seat that incumbent councilmember Richard McIver planned to not run for.

[14] During the August primary for Position 8, O'Brien advanced with 35 percent of votes and was set to run against second-place finisher Robert Rosencrantz.

[16][17] O'Brien ran for the newly created District 6 position for the Seattle City Council, primarily covering Ballard, Fremont and Green Lake.

[20] Facing unfavorable polling results and opposition from groups like the Metropolitan Chamber of Commerce, in February 2019 O'Brien announced he would not seek reelection to the Seattle City Council.