[3] Details of the next few years are unclear with most accounts indicating he was admitted to the bar in 1862 and Porter being wounded at the Battle of Gettysburg during his service in the Union army.

[2] In 1865, shortly after the American Civil War ended, Porter married Julia Sophia Trowbridge.

[2] President Ulysses S. Grant nominated Porter to become an Associate Justice of the Arizona Territorial Supreme Court on February 20, 1872.

During the trip he was flabbergasted by the climate and complained to United States Attorney General George Henry Williams that temperatures reached 114 °F (46 °C).

The U.S. Congress had passed legislation authorizing the territorial legislature to override a veto with a two-thirds vote.

[7] During his time on the bench, Porter acquired extensive land holdings in downtown Phoenix along with mining properties throughout central Arizona.

At the same time he and Charles Silent were active in encouraging Eastern venture capitalist's efforts to invest in the territory.

He turned down an opportunity to run for Territorial Delegate to Congress in 1878 due to the declining health of his first wife.

[12] During the legislative session his "untiring energy and indomitable will" help ensure passage of legislation creating a territorial normal school, territorial insane asylum, and authorization of a railroad link between Phoenix and the Southern Pacific Railroad at Maricopa.

As the session's members traveled by Pullman coach to the new Capital, Mayor Porter helped pay for the entertainment and personally presented each of the legislators with a new silk hat.