He was also a staff member of the Seattle-based Washington Roundtable, a non-partisan policy research group composed of the chief executive officers of the state's largest corporations.

On July 19, 2005, McGavick announced that he was forming an exploratory committee for a 2006 bid for the Washington United States Senate seat held by Maria Cantwell.

[11] McGavick's wife, Gaelynn, is an attorney by training who has experience in the arena of health care policy, at one point working as a liaison to the White House for the American Hospital Association.

In early January 2006, McGavick began his campaign full-time for the U.S. Senate, saying he would bring a "Northwestern voice of civility" to what he described as a culture of infighting in the nation's capital.

[12] For most of July, the McGavick campaign traveled around the state in an RV, making stops in: Seattle, Sedro-Woolley, Oak Harbor, Anacortes, Bellingham, Friday Harbor, Port Angeles, Forks, Clallam Bay, Bremerton, Belfair, Satsop, Aberdeen, Raymond, South Bend, Seaview, Naselle, Cathlamet, Vancouver, Goldendale, Pateros, Brewster, Republic, Colville, Spokane, Pullman, Clarkston, Pomeroy, Dayton, Prosser, Ritzville, Moses Lake, Leavenworth, and Yakima, among others.

In the May 2006 edition of the Weekly Standard, McGavick made the argument that Iran should be banned from the FIFA World Cup due to its nuclear weapons research program and statements by Iranian President Mahmoud Ahmadinejad that deny the truthfulness of the holocaust (which is a criminal offense in the 2006 World Cup host country, Germany).

The FEC dismissed the case, stating, "The commission concluded that these payments were ordinary employment-related compensation made irrespective of Mr. McGavick's candidacy.