He lost in a landslide to Democrat Isabella Greenway, who garnered 73% of the vote to become the first woman from Arizona to go to Congress.

[6] He also graduated from Northwestern with a law degree in 1898, after which he moved from Evanston, Illinois, to Phoenix, Arizona, where he remained the rest of his life.

[4] In 1913 he became a member of the Committee of the One Hundred and Twenty Five, a citizen's representative group to discuss and help decide the framing and organization of Phoenix.

As part of the process, the committee nominated fourteen of their number to run for the Board of Freeholders, who would draft the new charter.

[15] The freeholders proposed the new charter in August 1913, and it was accepted by the citizens, changing Phoenix's form of government from a mayor-council system to council-manager.

[20][21] Wilkinson and Hall defeated O. S. Stapley, an incumbent, and H. A. Davis, who had served in the first Arizona State Senate, in the November general election.

[32] During the 5th legislature, Wilkinson introduced Senate Bill 125, the "Governor's Cabinet Measure", which was a massive reorganization of the state government.

While the bill passed the Senate with a party-line vote of 10–9, it never made it out of the House's Committee on Efficient Government, which was controlled 4–3 by the Democrats.

[38] However, he was soundly defeated in the November general election by the Democratic incumbent, Lewis W. Douglas, by more than a two-to-one margin, 75,469 to 29,710.

[4][46] He was one of the founders of Banner - University Medical Center Phoenix, helping to raise the $40,000 needed to begin the construction of the hospital, and served as its chairman of the board from 1911 through 1921.

The first step to begin the process would be the creation of a highway running between the two cities, in order to promote commerce.

[57] The line would need to have had the Southern Pacific and El Paso and Southwestern railways merge, which needed approval from the Commerce Commission in Washington, D.C.[58] The hearing took place in September, and Wilkinson was part of the Arizona contingent which traveled to the U.S. Capitol to argue in favor of the proposal.

[59][60] Construction on the new line commenced in January 1925 near Picacho, with Wilkinson, along with F. J. Elliot, president of the Phoenix Chamber of Commerce, throwing out the first shovelful of dirt.